I have never written any statistic of my players in excel. I remember that I have bought GK on screenshot at his rating 64 and all auctions were won for only 1-2T. That is reason why my team now has over 40T with 35T/season strategy, that is success.
With 35T per season I don't care too much about growth itself. That means I don't buy packs so I can't heal every player or power train anyone. So far my strategy is to buy expensive nordgens and use them for few seasons.
I keep in my head few names of fast growing players, so usually I try to use them in 2 matches per day (league + cup or CL).
If I had any statistic, I would post them, sorry but there is none... I usually take screenshot of my big matches and long-term players statistic.