Answer:
2009
Explanation:
During the 1990s and early 2000s, the overall sale of more efficient cars decreased due to more strict fuel efficiency regulations on trucks and SUVs that actually increased the total number off trucks and SUVs sold, decreasing the average fuel efficiency by 1 mile per gallon.
It wasn't until President Obama passed stricter fuel efficiency regulations for all types of passenger vehicles that the overall efficiency increased.
