A lot of the most successful northen countries, especially in Europe. are 80, 85, 90% homogeneous. Most of the immigrants come from similar countries.
Sweden is 80% "homogenous", it is true. And most of the immigrants come from similar countries like Iraq, Syria, former Yugoslavia, Iran, Poland and Somalia, you are right.
In the US, you're talking more around 65%~, and because of the size of the country, even those are divided in 2 (eg: on health care).
In the US as a whole, you are talking about 72%. In Maine, New Hampshire, Vermont and West Virginia its almost 95%. The US as a whole is pulled down by a handful of your biggest states, which have almost as many white Hispanics as white Americans. But keep kidding yourself that your problems are caused by not having enough Aryans.