Yes! The stock exchange runs on xp, nhs services i.e hospitals & drs use it still, big screens in sports on tv run on it......xp is the most used os in the world, some will have 7 because they upgraded when vista came out only to find it was ( insert lots of swearing here )!
If i had to guess 70%ish would be XP & the rest will be 7, 8 & other os ( apple, ubuntu etc ) which are aimed at editing & designing more than anything else! When you look back apple & android os only recently exploded into the market as serious rivals to ms who dominates it.....the rest are mearly a spec!