If the number isn't to big, you could count the number of rounds you have played since turning legend, look at your stats to see total number of stroke play games played, and take off the number of legend games. This will give you a number of Stroke rounds played when you turned legend, note this number. From now of you can just check your stats, little maths and know how many games as a legend you have played.
I have approx 100 games as legend and still going up and down, but the movement is very small, 0.05 for a good or bad round.
Kindle