Hi I Have Been On Levlen Ed For 4 -5

Hi I have been on Levlen Ed for 4 -5 months now, I have taken the pills properly and followed the instructions with them. So I was wondering if I would be protected from pregnancy if I had unsafe sex with my boyfriend. We have been doing the pullout method for a while now with no problems and I was just wondering if I would be safe if I didn't make him use withdrawal?What would the percentage of pregnancy possibilites be?