If Toronto's streets seem tidier, it's because they are.

According to an audit released by the city Wednesday, the amount of litter on Toronto's streets has dropped by 40 per cent since 2002.

An independent firm conducted the annual litter audit by randomly choosing 298 sites across the city, with at least two from each ward, then counting the pieces of litter there.

In 2006, the survey found an average of 15 pieces of litter per site, compared to the 20 and 21 pieces per site in 2005 and 2004. The first 2002 audit found 25 pieces of litter in each area.

The audit showed that 27 per cent of the street litter was plastic products such as wrappers, bags and bottles, while 22 per cent was paper materials such as coffee cups.

Mayor David Miller credited both the city-run litter programs and Torontonians with keeping the streets free of trash.

"It's a virtuous cycle. When you invest, more and people start to see the city is more beautiful, then it's cleaner," he said, adding that people are much less likely to litter if the streets are cleaner.

Since 2002, the city has added several hundred litter bins on streets and beefed up the number of mobile one-person litter vacuums sucking up garbage along roads, city officials say.

Fifteen litter vacuums have been purchased in the past few years, said Richard Butts, the head of the city's solid waste management.

"We get them out earlier so they can clean up more," he told CBC News.

Picking litter off the streets of Toronto costs the city around $20 million a year.

The mayor and city staff said they are determined to cut down on littering even more by next year, with the 2007 goal set at 12.5 pieces of litter per site or a 50 per cent reduction in littering since 2002.

The survey was paid for by the City of Toronto.