Why Do I Have Well Defined Abs on Top but Not on the Bottom?

I work out often and exercise and all that, but I often wonder how everyone manages to get so ripped. My top abs are well defined and you can see them, but my bottom abs lack it. All in all I'm just curious as too why the top abs develop more or before the bottom abs do.

Suggestion:

It's body fat percentage.

We lose body fat according to genetics. Both men and women will typically lose most of the fat from the limbs first, than chest and the love handles and lower abs are the last place for men to lose and for women its the hips / butt.

With that being said, I am going through the same issue. I was 5'11" and 172 when I felt my pants getting a little too tight. I have since lost 10 lbs and have developed my abs. I still have a little more to lose on that last place, the love handle's and lower abs. I figure another 7lbs will do it.

It's around the 10% body fat area that the abs will really start looking cut up. It would only take you about a month or two of exercising and eating right to get that look.