Around (best guess) 350-400 EMs. Mostly GTBs, next WMS, and then CC and others. Some rare, some duplicate as expected. Both in my collection and other larger collections. Of course way back in the day on location (tons that were new releases), at shows like Allentown, York, TPF, PPE, pacNW shows. About as many at other locations like PHoF, Banning, VFW, and many more. It adds up very quickly.
Its my guess and limited recent memory with a tad of understanding TT is relocating south or going to, and is in the process of finding homes for his collection. Witnessed a recent claimed sale from RIs collection of EMs being sold off in part to make room for modern games. After all, business is what pays the bills, and eventually you have to pay or shut down. These collections are amazing, really quite nice and complete, and I believe TT, RI (2x) and TA (hand built) all have TKO. Rare stuff, hard to find, and in generally really good condition. So, go enjoy them on location and at these arcades before they shut down. As TA has said so well "... there is no guarantee these games will be here tomorrow, so come on out and see them before they go away." After all, fear of loss marketing does work.
I have a sad feeling eventually RI and company will be mostly crane games (jk).