I'm 5'8 and was supposed to be 5'11. Life would be easier if I was taller, right? Well for US female 5'7 is above average, at least in this time span. Over time, the trend looks like people in US are getting bigger and stronger (not just fatter). This is proven by looking at past measurements of US males and females from let's say 1950.
As far as other sizing goes...you cannot determine by clothing size now, it is all screwed up due to marketing (i.e, let's make a bigger size a smaller number so females will buy it..). For example, Marylin Monroe was like a size 12 to 16 well in most of todays standards that is a size 6 to 8 in women/and maybe junior girls. Just as where 1950s size 4 is usually todays size 8 in womens. However, this doesn't mean we have gotten fatter, it just means bigger and stronger and more bone mass maybe.
And there is no such thing as a size 0 or 00 that really confuses the issue when shopping, if I meet whoever thought that one up I will punch them.