CRISTIAN SALAZARNEW YORK (AP) â¿¿ Giving letter grades to the thousands of restaurants in New York City â¿¿ from humble delis to celebrity chef-powered eateries â¿¿ has been a boon to business and has led to a decline in the number of cases of salmonella food poisoning, the mayor and health officials said Tuesday. Some city council members, however, say the grading system is far from perfect and needs to be reviewed. Restaurant industry representatives complain of excessive inspections and burdensome fines on small businesses. Mayor Michael Bloomberg, Health Commissioner Dr. Thomas A. Farley and other health officials announced initial data Tuesday showing salmonella infections decreased by 13.5 percent over the first full year the city has used letter grades. The Health Department said 1,296 cases of salmonella were reported in 2010 and preliminary data show 1,121 cases in 2011. Further emphasizing that sanitary conditions are improving, the officials said more than 72 percent of the city's 24,000 restaurants earned "A'' grades compared to 65 percent a year ago. They also highlighted the most recent tax data available showing restaurant sales were up 9.3 percent from June 2010 to February 2011. "It just may be that clean kitchens are as good for business as clean air is when a restaurant is smoke-free," Bloomberg said at a news conference held at Zero Otto Nove in the Bronx. The city started handing out letter grades in July 2010. Restaurants can get an A, B, or C, based on points for sanitary conditions. Restaurants have to post the grades in a visible area such as a street-facing window or door. Common sanitary violations include food stored at improper temperatures and evidence of vermin. The largely positive announcement, which included the release of survey results showing New Yorkers largely approve of the grading system, came a day before the City Council was expected to hold a hearing on restaurant letter grades.