Does anyone have solid statistical information on UID/MP cases?

I was looking at Namus today and recording the number:

Missing Persons (open cases)
Male - 5,674
Female - 4,484

UID (open cases)
Male - 7,228
Female - 2,055
Unsure - 408

I was rather shocked at the numbers. Males are under reported compared to found and females WAY more often reported than they are found. I was wondering is the female UIDs are IDd much more often than the males and so they are solved and fall off the open list.