6. Honda Civic: 18.5M units sold

The only surprise about the Honda Civic being on the list is that it’s in sixth place. Despite the recent model’s sales droop, the Civic is still one of the most popular cars in history. The Civic has been everyone’s affordable Honda since its debut in 1972, available in hatchback, coupe and sedan forms through multiple generations. In more recent years, the Civic can also be purchased with natural gas or hybrid powertrains, offering further savings through fuel efficiency.