Americans took more trips on public transportation in 2013 than in any other year in more than five decades, according to the American Public Transportation Association’s annual report, released Monday.

That’s 10.7 billion trips on buses, trains, and subways – the highest number since 1956, back when Americans were heavy users of big-city transit because they were more likely to live in town than in outlying (and car-reliant) suburbs. Americans’ use of public transit also increased from 2012 to 2013 by about 1 percent, with most of the gains in use of heavy rail, including subways and elevated trains, according to the report.

But the higher numbers of people turning to public transportation aren’t just the result of population increase or the cost of a tank of gasoline.

Public transit ridership has outpaced population growth since 1995, with public transportation use up by about 37.2 percent compared with population growth of 20.3 percent. Plus, the rise in ridership is despite a drop in gas prices in recent years. The number of public transport trips last year surpassed the 10.59 billion trips taken in 2008, even as gas prices have come down from about $5 a gallon to about $4, upending the assumption that high public transportation use is tied to gas price increases, according to The New York Times.