"There has been little net change in the size of the American Muslim population in recent years due to conversion,” according to the Pew Research Center. “About one-in-five American Muslim adults were raised in a different faith or none at all. At the same time, a similar number of people who were raised Muslim no longer identify with the faith.”
I would take the above paragraph differently, 1 in 5 is a big change, going both ways. The media has focused on how unusual it is for someone to leave Islam; and also, considering how different Islam is from American mainstream culture, I am surprised how many join it.
They may be combining data from the “Nation of Islam” and its derivatives with “Middle East Islam”, which may be a different dynamic. I would like to see that separated out.
Islam is itself a whole culture including, but going beyond what Christians regard as “religion”, just as with Judaism. So surveys like this one many be underestimating, or overestimating, the “Muslim population”.