These are useless stats, I expect you to know the flaws of median calculations, which is just picking the number in the middle, it doesn't really tell you anything, 5 people with over a 1 million, 1 with a few hundreds, and 5 with nothing, will appear as a median as having a few hundreds.
It also doesn't factor in the fact that Somali's are not economic migrants unlike Ethiopian's not fleeing civil war, it doesn't factor that most Ethiopian's, Eritreans and even Sudani's classify themselves fraudulently as 'Somalis' for much of the 90's and 2000's because it was the only way to get refugee status 100%.
I know it means that but this is statistics for a big group of people, not something so fluctuating and small. There's also the stats the US published too that another user posted^. And actually most (currently) Ethiopian adults came through the Derg era, its the newer ones that are economic migrants.