In 2006, about 8 million more people spoke a foreign language at home than in 2000. Nationally, one in five (19.7 percent) over age 5 spoke a language other than English at home, compared to 17.9 percent in 2000. Among states, California (42.5 percent) had the highest percentage in this category, followed by New Mexico (36.5 percent) and Texas (33.8 percent). About one in 10 California households were linguistically isolated, which means everyone 14 or older in those households had at least some difficulty speaking English.

All people born outside USA are using METRIC system.
20% of the population used to Metric is not a small number.
I guess illegals are not included