Serial Killers By Decade Worldwide
Numbers of serial killers by decade reflect only known information since 1900, source: Radford University/FGCU Serial Killer Database
As you can obviously notice from the chart, the number of serial killers saw a decreasing trend starting with 1980’s. This could have multiple reasons and I will speculate now and say that probably one of the reasons is advanced methods and science used in investigations. Nevertheless the decreasing numbers of serial killers both US and internationally is a good sign.
It might look from the numbers presented that US has had far more serial killers than internationally combined, however keep in mind that numbers are only the ones confirmed and also there are different definitions of serial killers internationally.
If you want to see more statistics then go here