The latest campaign spending numbers show that Mayor Michael Bloomberg has spent $64.8 million dollars on his re-election bid so far, about 17 times the amount spent by his Democratic rival.

At this point in his 2005 campaign, Bloomberg had only spent $47 million.

The billionaire mayor, recently ranked by Forbes as the eighth-richest man in the United States, has spent $28 million since mid-July.

About one-third of the campaign money - $22 million - has paid for television ads.

A recent ad shows unnamed people criticizing the mayor's rival, City Comptroller William Thompson, saying he practices "dirty politics" and "was not able to handle the Board of Education."

The mayor also spent $9.9 million for campaign mailings, $7 million for consultants and $1.9 million on polling data.

"This is a campaign and we each have to tell the public about what we would do if we got elected and why the public should believe that we can do it," said the mayor.

Thompson is struggling to keep up with his opponent's spending. He is participating in the city's campaign finance program and has raised $8 million so far in private contributions and public matching funds. Of that, he has spent $3.8 million on the campaign.

Bloomberg is outspending Thompson at a rate of 17-to-1, but the Democrat is confident that he has enough campaign money.

"Those of us who are within campaign finance, as opposed to Mike Bloomberg, who continues to spend that obscene amount of money, Those of us in campaign finance, small contributions from prom people in the city of New York are matched on almost a nine-to-one basis," said Thompson. "So everyone looks and says 'Oh gee, look what you raised,' but they're not looking at the number of matchables that we're raising. So I'm very comfortable in the pace that we're raising money."

On Friday, Thompson picked up the support of the electrical workers' union, which supported the mayor four years ago. The endorsement came exactly one year after Bloomberg announced he would change the voter-approved term limits law so he could run for re-election.