Who's supplying Arafat $90,000,000/month?

Michael Kelly 5/8/02 column http://www.washingtonpost.com/wp-dyn/articles/A49814-2002May7.html

The above is from Michael Kelly’s sarcastic column about Arafat as a partner in the peace process. Is Kelly saying that Israel is providing $90MM/month? the U.S? the EU? Arab states?

Aside from the $90MM, who or what keeps the PLO supplied with funds to pay the salaries of its security forces, administrators, etc.? Do they have a base that can be taxed?