Dress sizes

What is with the dress sizes in this country? Why do women's clothes go up two inches at a time? Size 10 = 36 inch hip (I think); size 12 = 38. Where did the 37 inch hip go?

Same with bras: 32, 34, 36 etc.

All my measurements are odd numbers because I am a non-conformist. I also find it difficult to get clothes that fit properly. I went into a shop a while ago and tried two different sized trousers and neither pair fit. So I asked the girl working there if they had a size 11. She laughed and said, "Yeah, it's annoying isn't it? I'm a size 9."
Another rebel.

Models have only even measurements on their busts, waists and hips, eg 36, 24, 34 or some such. This is to do with their genetic codes.

When it comes to buying a dress (if you do that kind of thing), what if you are a size 14 on top and 18 on the bottom? How many of us are the same size all over? Is this why not many women wear dresses? Or is feminism why not many women wear dresses? So many questions...

Out of necessity I tend to go for the top and skirt option. But in the winter I need tights or hold-ups and they are expensive and don't last very long and I have to keep getting new ones and the whole thing is pissing me off.