How many additional people would the US have had if it kept its pre-1882 open borders policy?

Futurist

Ad Honoris
May 2014
19,505
SoCal
#1
How many additional people would the US have had if it kept its pre-1882 open borders policy? The US historically had open borders but began closing its doors to various immigrants--first to Chinese immigrants in 1882, then to some other Asian immigrants in 1917, then largely to Europeans (especially Southern and Eastern Europeans) in the 1920s, and then to Latin Americans in 1965 (which in turn compelled a lot of Latin Americans to come to the US illegally since they could no longer do it legally).

Anyway, how many additional people would the US have had right now if it would have kept its traditional open borders policy for all parts of the world? Also, what effects would this have had on the US--including on the economy of the US and on US politics--as well as on the rest of the world?