A very large one. In Clark county, which has over 2/3rds of Nevada's population, 2 years of a foreign language is required to graduate high school but your first chance to take one usually isn't until 8th grade.

So 100% of graduating students in Clark County will have taken a foreign language class, and assuming roughly equal overall population ratios with school age children Nevada would be at 70% minimum if it was based of at graduation. However since the first 8 years it isn't an option you drastically tank the numbers like you mentioned.