Passage: As of 2006, California had an estimated population of 37,172,015, more than 12 percent of the U.S. population. This includes a natural increase since the last census of 1,557,112 people (that is 2,781,539 births minus 1,224,427 deaths) and an increase due to net migration of 751,419 people. Immigration resulted in a net increase of 1,415,879 people, and migration from within the U.S. produced a net decrease of 564,100 people. California is the 13th fastest-growing state. As of 2008, the total fertility rate was 2.15. The most recent census reports the population of California is 39,144,818.

Question: Based on this passage, what percentage of the country lives in california?
Steam of consciousness below:
The relevant information is: As of 2006, California had an estimated population of 37,172,015, more than 12 percent of the U.S. population.
So, the answer is 12 percent.