It is bad news I guess.
Even police is better in discovering it it is clear growing pattern in number of people that are trying to accesses such material on web and amount of material available.
It is very good question about limited law enforcement to deal with this - this is problem on global scale as I see it and we have to face it: police and other agencies are terrible under-capacitated in knowledge and technical tools and legal actions are not bringing desired efforts at all. Otherwise we will have different picture- those are my 2 cents after considering couple of decades of fights with this type of crimes.
I don't want to sound negatively but I'm almost certain that gap in capabilities to fight child abuse/porn and related crimes is widening and legal enforcement institutions are seriously falling to catch the race...