D.C. Metro ridership has declined in recent years amid concerns from riders about safety and reliability. (WUSA9)

Metro, in an unusual acknowledgment, says breakdowns and other service failures appear to be contributing to a steady, years-long decline in ridership that is causing financial stress for the transit agency and could lead to fare increases.

The persistent drop in annual rail ridership since 2010 results not only from economic and lifestyle changes in the Washington region, according to a Metro budget report made public this week. The report cites “preliminary evidence” that “concern by customers over service quality and reliability” also is taking a toll on ridership.

The document — prepared as a revenue briefing to be presented to members of Metro’s governing board Thursday — includes an uncommonly candid recognition by the agency that subway performance woes have become so chronic that more and more commuters are abandoning the system, which has worsened Metro’s money problems.

“Metrorail is struggling to provide reliable service to customers,” the report says. It cites three huge disruptions in the past 10 months, notably the Jan. 12 incident in a Yellow Line tunnel in which smoke from an electrical malfunction enveloped a stalled train, sickening scores of passengers, one of whom died of respiratory failure.

The report also says that rail on-time performance has been “consistently below target, particularly since the opening of the Silver Line” in July 2014. It adds that riders “are experiencing more unpredictable travel times, and must budget more time to reach their destination.”

Other factors in the ridership decline include federal job cuts, the popularity of biking and car-sharing, the growth of telecommuting and a reduction in the federal tax benefit for using public transportation, the report says. Those factors have been mentioned in many past budget documents. But rarely has Metro been so blunt about the impact of its service shortcomings.

“I think it’s a very straightforward and honest report,” Board Chairman Mortimer L. Downey said Tuesday. “When I read it, my observation was, this is much more explicit than ever about performance being part of the revenue problem. And we should be happy to get the report. It’ll help us focus on what we need to do.”

Rather than being isolated incidents or aberrations, Metrorail foul-ups are a daily norm. On Tuesday, for example, in addition to rush-hour slowdowns that are expected to last into next year on the Silver, Orange and Blue lines, there was a large-scale service disruption on the Blue and Yellow lines during the evening rush hour because of a problem on tracks shared by the lines between the National Airport and Braddock Road stations.

Starting in 1996, when Metrorail recorded 150 million passenger trips, ridership increased annually for 13 years, peaking at 225 million passenger trips in 2009, according to the report. “However, starting in 2010, through 2015, daily rail ridership has declined by five percent,” the report says. The trend means that Metro counted about 214 million subway-passenger trips in the fiscal year ended June 30.

Because rail fares account for a major portion of Metro’s annual operating revenue, the agency’s budget managers could include fare increases for train users (as well as bus riders) in their proposed spending plan for the fiscal year that begins July 1. The plan is scheduled to be submitted to the board next month.

To keeps its trains and buses running, Metro depends most heavily on financial contributions from Washington-area jurisdictions served by the transit system. For the current fiscal year, which ends June 30, the overall budget is $3 billion, including money for long-term capital improvements and $1.8 billion for day-to-day operations.

After several major rail disruptions in recent months and revelations about Metro’s safety and infrastructure woes — underscored by the Jan. 12 smoke calamity — the jurisdictions have balked at increasing their transit subsidies. In addition, the regional leaders remain concerned that the transit agency is without permanent leadership, and has been since former general manger Richard Sarles retired in January.

Besides using the subsidies, Metro also relies heavily on in-house revenue to finance its operating budget. Most of that money comes from subway and bus fares, which were projected to exceed $800 million this fiscal year. As they do every year, daily subway commuters will contribute the bulk of that revenue.

With expenses continuing to go up, local jurisdictions reluctant to boost their contributions and rail ridership trending downward, the agency said, it might have to extract more money from customers.

“I will wait for the discussion,” Downey said, declining to predict whether fares will go up next year. “I know it’s certainly going to be a subject of debate. But I don’t have my mind made up on it yet — other than to say that there are revenue gaps in the budget and we’re going to have to find some way to close them.”

The board’s policy is to not increase fares two years in a row. For the budget period that ended in June, there was a 3 percent fare hike, raising the cost of the typical subway ride to $3. There were no fare increases for the current fiscal year, meaning that the board’s policy will allow for price hikes to be on the table for next fiscal year.

A move to raise fares almost certainly would spur howls of protests from many riders who have grown weary of persistent breakdowns and delays.

Although the report specifies three major incidents this year, Metro has been plagued by smaller problems, also annoying and sometimes frightening for riders.

Besides the Jan. 12 incident, the report mentions an Aug. 6 derailment in which a train that was not carrying passengers derailed between the Smithsonian and Federal Triangle stations. The derailment forced a day-long shutdown of the two stations and crippled a big stretch of the subway, stranding tens of thousands of commuters.

Then, on Sept. 21, a fire destroyed a subway power substation near the Stadium-Armory station. For at least six months, while Metro works to fix the substation, commuters on the Orange, Silver and Blue lines will have to endure daily rush-hour delays, fewer trains and more sluggish rides, the transit agency said.

“There is preliminary evidence that these events are impacting ridership,” the report says, “though additional analysis is required before definitive conclusions are drawn.”

Beyond inciting anger among commuters, a proposal to raise fares would undoubtedly spark boardroom fireworks at Metro headquarters. With the addition of several new members this year, the board’s meetings have become more contentious, with members sharply criticizing agency managers over rail service problems.

“I’m going to get my flak jacket ready,” Downey said.