Just wondering if anyone can point me in the right direction for the clothes sizing sytem used here for business trousers and other more formal wear.

I'm used to waist measuremnts in cm's or sometimes ye olde inches. I would try pants in a size around 86cm or 34 inches. Here, I seem to be a "50". From what I have deduced, a 50 is slightly smaller than an 86cm waist, with average length legs. Then a "100" is the same trousers with longer legs, and I guess a 25 would have shorter legs. A "52" is the next size waist up....

Anyone know of a guide to this system? Is it a Swiss/Euro etc thing?