The final weekday of May, like most others in the month, passed without a formal White House press briefing. On the dozen occasions in May when President Trump's spokesmen conducted question-and-answer sessions with reporters — on camera at the White House or off camera aboard Air Force One, as deputy White House press secretary Hogan Gidley did on Thursday — the average duration was 17.6 minutes.

The length of these Q&As has declined in each month since January, when a typical exchange with reporters lasted about 30 minutes.

At the current rate of decline — about 3 minutes per month — press briefings will disappear altogether by November. Trump mused on Twitter last year that “maybe the best thing to do would be to cancel all future ‘press briefings.’ ”

An end to White House briefings seems unlikely, given the benefits afforded Trump, particularly during the formal, televised sessions. Whatever the day's news, White House press secretary Sarah Huckabee Sanders gets to make an opening statement about anything she chooses, live on every cable news channel.

Sometimes Sanders uses the time to read fan mail to the president, as she did May 17, when she shared a letter from an 11-year-old boy who wrote: “I listen to your talks, and I went to the inauguration and saw you. You're awesome.” On that day, the briefing lasted 16 minutes, four of which were devoted to touting Trump's donation of his second-quarter salary to the Department of Veterans Affairs.

To cancel the briefings would be to give up a major public-relations platform — an un-Trump-like move. But to gradually pare down the briefing time would be to limit the White House's exposure to tough questions. That is what's happening now.

Tracking the duration of Q&As is not the only way to measure media access, of course, but The Washington Post's Philip Bump noted last week that the Trump White House is stiff-arming the press, according to other metrics, too.

And the Erik Wemple Blog on Wednesday chronicled Sanders's habit of quashing follow-up questions and speeding through briefings with variations of “we're really tight on time today” when, in many cases, the time constraints are self-imposed.

Wednesday's session, the last televised briefing of the month, was a good example. First, the White House scheduled no briefing. Then it set one for 2:45 p.m., 45 minutes before the president would host a fitness-themed event.

The result was easy to predict: Sanders would arrive a little late and adjourn a little early to allow herself and the press corps plenty of time to migrate from the briefing room to the South Lawn. That's exactly what happened. The briefing lasted 16 minutes.

Around this time last year, I wrote that White House Q&A sessions were getting shorter and shorter. The average in May 2017 was 30.8 minutes; it had been 47.6 minutes in March.

The trend continues as the White House steadily curbs journalists' ability to pose questions.