Or, do you mean once you stop taking bc pills? If so, it all depends on how long it takes your body to readjust to having a natural cycle again. Some posters report taking months to get back to a regular menstrual cycle, which is of course needed to conceive. Once you get back to a regular cycle, the chances are probably about like anyone else in your age bracket.
If you meant what are the odds of getting preggers while ON the pill, I believe the pill is said to be 99% effective at preventing pregnancy, which would translate to a 1% chance of getting preggers while on it.
Well, they are better if you are not taking birth-control pills.