Why do we owe the state tax every year?

For the past three years since I have started using Turbo tax we have stopped getting refunds and always have to pay the state back. This year it has risen to paying over $800. My husband makes around 60 thousand and I work part time and make 15 thousand. We have though 9 kids/dependants. They take out like about 700 in state tax on him and 350 on me. We file jointly. Are we not having enough taken out each year? I'm getting tired of having to pay these large sums.