Well given the vast majority were deficit spenders, I still have to break them down. Reagan was most certainly not the worst. He added $1.6 trillion to the debt as did Clinton. The two Bushs were the worst culprits.... especially the current one.
Well, looking at deficit spending as a percentage of GDP Reagan was the worst, followed by Bush I, followed by Bush II and then Clinton who isn't even close to the others. So, in reality Reagan was the worst culprit.