Since the 50s, thousands od people claimed to have been abducted by Aliens.
In the USA alone, numbers go from 1700 (seems very low) to 5% (seem very high).
But let's see what this numbers mean.
The population of the USA is some 300 million, or 5% of the world's total.
If we go for a number of 170.000 abductees in the US (about halfway between the extreme numbers), and consider this as 5% of the world, we get 3.400.000 as planetary total.
Now, with a life expectative of 75 years, the aliens have 27.375 (75 years x 365 days) to do the kidnapping.
That gives 124 abductions every day.
Are those little green men busy or what?