One of the ongoing questions about the administration of President Trump has an answer — at least, in part.

Since his first month in office, with his first weekend forays to his private retreat in Florida — Mar-a-Lago — questions have been raised about the cost of those trips. This isn’t simple to figure out, given that the total includes costs incurred by various government agencies as well as costs associated with Trump’s Secret Service protection. Although estimates of the cost existed, it would require a great deal of information from across the government to come up with an accurate total.

The Government Accountability Office gathered that information. On Tuesday, it released a report looking only at Trump’s first four trips to Mar-a-Lago as president: on Feb. 3-6; Feb. 10-12; Feb. 17-20; and March 3-5, 2017.

The total? Just under $14 million, for an average cost of $3.4 million per trip. That includes about $8.5 million spent by the Defense Department and $5 million by the Department of Homeland Security. It also includes about $60,000 paid directly to Mar-a-Lago itself, $24,000 of which was for lodging for Defense Department personnel and $36,000 for operational space used by DHS.

The immediate question, of course, is how those costs extrapolate to all of Trump’s visits. This invariably leads to some apples-oranges problems, but we can make some reasonable estimates.

We know, from having tracked his trips over time, that Trump has visited Mar-a-Lago on 19 occasions as president, spanning 51 nights.

Some of those trips, as shown above, were longer than others. The GAO report notes, however, that much of the costs of the trips were incurred by the air travel to and from Palm Beach, including transporting people and material needed to support the president while there. (About $7.4 million of the total was spent by the Air Mobility Command and 89th Air Wing.) If we, therefore, assume a blanket average of $3.4 million per trip, regardless of duration, the total the government has spent on Trump’s trips to the resort tops $64 million.

We can probably assume that the money spent at Mar-a-Lago itself was incurred on a nightly basis, given that it deals with hotel rooms and operational space. If that’s the case, the government probably has spent nearly $370,000 at Mar-a-Lago itself to protect the president since Trump was inaugurated.

How does $64 million in costs stack up against other government spending? Well, Trump has complained on several occasions about the cost of the investigation being conducted by special counsel Robert S. Mueller III, including in December.

Although that figure is higher than the $25 million the inquiry — involving Russian meddling in the 2016 presidential campaign — is reported to cost, it’s clearly substantially lower than the amount that probably has been spent on Trump’s trips to Palm Beach. Given that the Mueller investigation has also probably paid for itself, given the assets it has seized from Paul Manafort in particular, there’s not really any comparison.

Trump also canceled a joint military exercise with the government of South Korea last year, citing the cost of the exercise. That cost? About $14 million — the cost of those first four trips Trump took to Florida.

One of the more remarkable aspects of the new figures from the GAO is that the figure is significantly higher than some of the existing estimates of the cost of his trips, which were derived from an analysis of a trip President Barack Obama took. That assessment, published in 2016, found that a trip Obama took to Florida and Chicago cost $3.6 million. Estimates for the cost of Trump’s trips based on the Obama analysis landed at $1 million apiece, less than a third the average cost of the four considered by the GAO.

Our estimate of $64 million also errs on the low side, equating as it does the week-plus Trump spent at Mar-a-Lago in December 2017 with his three-day trip there in February that same year. What’s more, it excludes every other trip Trump has made to one of his own properties as president, including to his private club in Bedminster, N.J., and his frequent forays to his golf club in Sterling, Va.

The mystery surrounding the costs of Trump’s travel lives on.

After a flood of charity events left Mar-a-Lago, pro-Trump groups are trying to make up the lost business. (Jenny Starrs/The Washington Post)