There's definitely a hit from the financial crash, but there's also been no increase since that drop for four straight years, during which the economy has presumably been recovering, albeit slowly; I suspect the decrease in retiring Boomers driving, decrease in new teenagers driving, increase in fuel efficiency, increase in non-driving entertainment like social networks, etc are all outweighing the hundreds of thousands of jobs that have been created since then. The huge growth in electric vehicles in the last 2-3 years[1] is probably to small to have an impact on that graph now, but give it a few more...

[1]http://si.wsj.net/public/resources/images/IV-AA467_ECARS_G_2...