I got Tennessee and Arkansas! Another two states down. That leaves 14 (and yes, Wyoming, that includes you). If you want to keep tally for your own records, the states left are:
Rhode Island (but its about to be claimed, so I've been told)
WYOMING! (I mean, come on!)
Fun Wyoming related site of the day: the official Wyoming Sate government's Kids Page. With numerous puzzles and stories, plus a dinosaur quiz, you're sure to spend hours learning all you need to know about Wyoming...if you're a ten-year-old child.