I just went over some of my stats from AdMob for the past year to see if something could be improved, and I realize that sorting countries by Network Request, I see some Asian countries like Cambodia, Philippines and Malaysia are in 3rd-5th place, but they have really low fill rate. The fill rate is between 10% and 30%, where for Europe and US the fill rate is usually around 55% to 70%.
And it is not like the ads that are shown perform badly, CTR around 3% and RPM around $1-$1.6 USD, so potentially I am missing out on a lot of revenue, if I compare the number of requests to other contries with the same amount, but higher fill rate.
Is that just how it is, or can I do something to improve fill rate in Asian countries, especially the ones mentioned above? Are there other networks that perform better in Asia?