That’s the number of trips that Americans took on mass transit in 2011, a 2.3% increase over 2010, according to the American Public Transportation Association (APTA). That’s the second-highest number of trips taken since 1957, after only 2008, when gasoline had hit a record average high of $4.11 a gallon. The increase in transit ridership last year reflects a healthier economy—more people employed means more people taking trains, buses and subways to work—as well as rising gas prices, which averaged $3.51 a gallon in 2011, the highest annual average on record. And even as more people take transit, we’re driving less—last year vehicle miles traveled dipped by 1.2%. Of course, even as transit use is growing, relatively few Americans actually take the bus or train—just 5% of the population (including me) regularly commutes by public transit. And today’s straphangers have nothing on the past—even with ridership on the rise, public transit use was far higher in the mid-1940s, before the great suburban car boom, when it was nearly double the current rate. Maybe that’s for the best—I can’t imagine the Q train getting any more crowded.