Checking back the Japan release date I found that we have at least 1 Optimus/ Convoy toy almost every month.
It should be the most frequent release for Optimus Prime for 20+ years.

2007
Jan- Revoltech Convoy
Feb- BT17 Black Convoy
Mar- Tele BW Convoy
Apr- Soprt Label Nike Convoy
May- ---
June- Protoform/ Leader/ FAB/ Cyberstomping Movie Primes, Paper Convoy, Robot Heros
Jul- Titanium/ EZ Movie Primes
Aug- Encore Convoy, Diabloack Convoy, Protoform Optimus repaint
Sep- Music Label Convoy, Sport Label Convoy Marine
Oct- Tele BW DX Convoy
Sep- Movie Night Watch Optimus
Dec- ????

Its happy(?) to be a Optimus Collector.

My wallet's not happy that I'm an Optimus Collector.

And how much of these are repaints? Guh.

Same here......