On the ARURF Odds

Being a main, I've been waiting to get to play Karma in ARURF. I have played 26 games, and here are some champion statistics:

• Karma on the enemy team: 5 times

• Karma on my team: 2 times (unwilling to trade)

• Karma that I have got: 0 times (not even rolled in dodged games)

• Sejuani that I have got: 2 times + rolled 2 times in dodged games

• Nidalee that I have got: 2 times (because she was free to play, don't even own her)

• Ashe that I have got: 2 times

At this point I begin to have had all available champions at least once, except for Karma. Karma being my highest mastery champion, I can't help thinking that the odds are personalized for each player so that players are enticed to play more until they get their favorite champion (if available at all).

Have you had similar experiences, or am I just having terribly bad luck?

Update: Played three more games and got yet another Sejuani, which I rerolled for Lulu, and then I got Lulu in both following games. The probabilities seem strongly biased.