“But considering the intermarriage rates in the reform and conservative communities, and the acceptance of paternal descent as “Jewish”, the question remains what percent of their communities are actual Jews.”
You’re so right,and consider that conservative geyrus is worthless as well.
By the way, the method of how Jewish population is tallied in the U.S.A. is that a sampling of people are called by phone and if the head of the household is claimed to be Jewish, the demographers consider and count the entire household as Jewish.
So halachically, there are far less Jews in the United States as officially stated and this would bring the true Orthodox proportion of the actual total of American Jews much higher than the secularists state.