A histogram titled, Distance driven for each vehicle at Nam's Gas Station, plots Number of vehicles, versus Distance, in thousands of kilometers, from 0 to 300, in increments of 50. Bar heights are approximately as follows. From 0 to 50, 3. From 50 to 100, 4. From 100 to 150, 5. From 150 to 200, 6. From 200 to 250, 3. From 250 to 300, 2.
How many vehicles are at Nam's Gas Station?