I agree with
@Swanky . I do not think 1 carat is average in the US.
If you live in affluent areas or cities, a one carat or higher is relatively more common (or more likely expected). I do, and so it has become common to see.
However, where I work, in what I consider to be a true middle-class community setting of a solid mix of blue and white collared workers, (which is more realistic), among my colleagues almost everyone has under a carat. I am probably one of the few who has what is considered a "very large" e-ring (1.54c). It garnered a lot of attention at work which I was engaged. And it's bigger than my previous boss's e-ring and my current boss's e-ring, (not trying to show of, just to give you an idea of things).
In our circle of friends from China (my husband and mine), those who are from wealthy families, there is that expectation that it better be one carat or higher.
However, for my circle of friends in the US, the carat size varies and even the stones vary a lot. I have see morganite, sapphire, emeralds, etc.
One of my friends had a 4 carat that everyone thought was a diamond. I knew from one look that it was a moissanite. (which is a beautiful stone, don't get me wrong, nothing against it, it has a beautiful brilliance that can shine more brightly than a diamond, she just kind of never publicly said whether it was a diamond or not, until her bf later told me in a hush-hush way that it was a moissanite.)
For the Chinese people that you see on social media with their 3 carat diamond rings, birkins and kelly, they do exists, however, they are just a small fraction of a very large country.
Those who come to the states to go to school and buy property, you are looking at the top 5-10% of wealth from China.
It feels like there's a lot of them, because China's population is just that big. So 5% of China's population (1.4 billion) compared to 5% of the US's population (332 million) is a lot more.
5% of 1.4 billion is 70 million.
5% of 332 million is 16.6 million.
It is something I have to remind myself from time to time.

Because I know I live in a bubble and my reality is not "ordinary".