I can't imagine there are too many of them in Iraq today. Kinda like that small Jewism community in Baghdad that stretched back to the Babylonian captivity. I think the report talked about 2-3 dozen survivors with one in her 30's, but most unlikely to survive the next several years.
According to what I was able to glean from some Mandaean web sites, they number around 50,000 total. Which is more, for example, than the total number of Karaite Jews worldwide (around 30,000).