In the month of december the amount of ads you would get in a single day could go from 5 to 10. There seems to be something different this new year because in the first 2 weeks I did not receive more than 3 ads. What is causing this decrease is not know but people are saying it could be because of the spike of new users in the last few weeks.
Have other people experienced the same thing with a decrease in ads? Let me know.
The only reason the Brave team gave is that in some country's there may be less campaign going on, you can check your country here: https://brave.com/transparency/