Pregnant on the Pill?

Ok so before our first child I was on the pill for almost 11 years. Took maybe 3 months to conceive. Well I’ve been back on it since he was 4 months, he will be 2 in June. My husband and I always use the pull out even with the pill. Well lately he’s been, let’s say, careless and not pulled out several times. What are the chances of getting pregnant? Not that I would mind another baby, just wasn’t planning it yet.