urf champion rate (lazy math about urf maokai)

there are 137 champions in the game and 10 players with 2 reroll. I got 9 maokai in 32 urf (not enough database hahaxd idgaf) 28,125% If the Champion slect was totaly random, statistics says maokai has 3 chances out of 409 to appear making it a 0,007 chance of getting it. As i m in holyday i totaly forgot how i could expend those math to 10 players so ill give up here but instead i got a 0,28 ratio of mao in my games. I'd like riot to show us the graph of champs played in urf. edit: 10(137+136*2)=30/4090 expanding it to 10 players would not change anything edit 2: oh also, I am a hater of arurf :)