A Golden Age of Serial Killers

I re-watched the excellent 2007 movie Zodiac last night, and wondered: what ever happened to serial killers? From my childhood (Wayne Williams) to my young adulthood (Ted Bundy and Jeffrey Dahmer), serial killers loomed large in my imagination. But with few exceptions (John Allen Mohammed), the serial murderers since then haven't made much of an impression on my consciousness, and some that did (Eileen Wourmos) only did so because they got movies. Was it my imagination, or did serial killing take a dive in popularity after, I dunno, the Columbine Massacre or 9/11?

Short answer: not really.

I turned to the Wikipedia page on Serial Killers and copy/pasted the table into Excel. I divided the "Proven Victims" column by years active to get a murders/year for each murderer or gang (this involved deleting duplicate entries in the table for each know member of the gang; each gang should only be counted once, though of course I could have missed some duplicates). I then summed up the murders / year for each year and produced the following graph:

With the exception of a spike in the 1930s almost exclusively the work of the Philadelphia Poison Ring, the serial killer phenomenon looks to be, basically, a product of the 1960s - 1980s crime wave, and the decline since seems to track the overall decline in violent crime since the mid-1990s. There doesn't seem to have been any noticeable impact of a single event as I had expected.

But that still leaves unexplained why even the extent serial killers don't really make much of an impression on me. Maybe I just stopped watching the news, or perhaps popular culture has moved on, or perhaps its just a numbers game: fewer serial killers make for fewer stars in the business. Thoughts?