It's very easy thing to do to lower the credit limit simply by giving the issuer a call and ask.

Is this the initial limit when you first got the card?  Sometimes, the issuer will increase the limit automatically over a period of time.  They use this opportunity as a loyalty-building tool and to increase balances.  Although larger line gives you more purchase power, it doesnt mean freedom. You will have to look at the debt to that limit ratio.