I've owned a 1991, 1996, 2001, and 2019. I thought I had them all but I think the small changes between 2001 and 2011 are being counted as a generation change.
Maybe @P. A. Schilke or one of the Administrators knows the answer.
According Wikipedia--T6 if that is how you count it?
"After an eight-year market hiatus, Ford introduced the fourth generation-Ranger for North America for 2019 at the 2018 North American International Auto Show, marking the first Ford entry into the mid-size pickup truck segment"