As you can see, a fair drop from 2003 until 2006 and now it has remained steady. Why the drop? I seem to remember something about Comreg removing anyone who had not renewed their licence from their database? Whatever the reason, there are currently about 1,500 EI stations with a licence. When you consider that the majority will probably not be active at all and another section who will rarely use the radio, there are probably only a few hundred active EI stations out there on the bands.
When you spread out that few hundred accross all of the bands, different days and different times of day, perhaps there are not so many of us after all.