i think interracial couples are still in the minority compared to the mass. most cultures still promote staying within your own race and oriental cultures probably enforce it more (in my opinion). i would also like to add that depending on your social circles and/or geographical location, you may or may not see more or less of amwf couples. amwf couples may simply just not be around where you normally hang out or places you normally go to.
from my own experience, most asian men who are culturally indoctrinated do not date women outside of their own race. most women who are primarily interested in asian men have an innate interest in the respective asian culture and, more than likely, will learn the language, culture, and move to that corresponding country wherein meeting up with and snagging an asian male counterpart.
there are outliers to this generalization since there are men and women out there who will date any race irregardless of any fact.