I notice this phenomenon in my closet right now! I have quite a few pairs of jeans I all bought from the same place. Exact same style and everything. However, the size 16's I'm buying now are much, much larger than the ones I bought 2 years ago.

At first I though, well, maybe those old ones are stretched out 14's, so I checked the label. Nope, they're 16s too.

I hate it because the old 16's fit me really nicely now, the new ones are WAY too big and are like a bucket around my waist. Yet, I think I'm too large for 14s still.
Grr!