Except for Haitians and maybe Venezuelans, every other nationality of immigrants in the DR (including expats) are well below 1% each. Oh yes, in this forum expats are very visible given this website is en English and focused mainly on expats. In reality, even in Puerto Plata you can spend days without running into an expat. That’s considering Puerto Plata probably has a larger share of its population as expats than typical major Dominican size and many expats from Sosúa/Cabarete go to Puerto Plata town for several reasons (shop at Jumbo, etc.) In most of the DR you simply don’t see expats, don’t even know the DR has a few. When you see that the towns where expats are most visible are in some villages like Cabarete or small towns like Sosúa or Las Terrenas, that is saying saying something.
One interesting detail to know is from where is the average English speaking foreigners in the DR? The US* (despite the recent grow of African American, the vast majority are white)? Canada? Or from the English islands in the Caribbean (which means almost all are black)?
* Dominican-Americans should be separate from the rest of Americans since it goes without saying most with US passports living in the DR probably are Dominican-Americans and Dominicans that simply were born in the USA.