I decided to login to Rockstar Games Social Club and check your numbers as they relate to GTAIV. They happen to have a time leaderboard for game completion time. There are about 2.6 million completion times listed online for the 360 and 2.2 million completion times listed online for the PS3 . Of those, 133,829 on 360 and 64,457 on PS3 were able to complete the game in 10 hours or less (in other words, 3.9% of players were able to complete the game in 10 hours or less).
This includes repeat finishers, and we can hazard a guess that repeat players took less time. Therefor, we can safely assume that fewer than 3.5% of people report your time. The median time to completion (again, including repeat players) was 35.04 hours so we can safely assume that the median time to completion for first plays was higher.
100% under 30 hours, huh?
"That puts you in", I kid you not, the top 0.2% of people who completed the game, which would put you in the top 0.005% of people who played the game or higher. You're one of the best video game players alive today! Amazing!