The first state to enact such a statewide system was South Carolina in 1995. Tennessee and North Carolina later enacted legislation imposing similar statewide systems. In many other states, the mandatory posting of restaurant grades is neither required nor prohibited statewide, which means it is purely a matter for local governments like cities and counties. In November 1997, a KCBS-TV sweeps news story called "Behind The Kitchen Door" focused attention on problems in Los Angeles's top restaurants. The station used hidden cameras to catch restaurant employees practicing unsafe food handling practices such as picking up food from the floor and re-serving it, vermin crawling near food to be served, and mixing uncooked meat and vegetables. The KCBS report also reviewed inspection reports, which have always been public records, but were available only on request (and at the time required an in-person visit to the health department), and found that many problems had already been expressly identified in the inspection reports but had not been adequately publicized. As a result of this report, in December 1997 the Board of Supervisors of Los Angeles County introduced a letter grading system already in use for some years in two other nearby counties, San Diego County and Riverside County. Instead of merely listing violations in a report, the restaurant inspection system was changed to a point system, with each restaurant starting each inspection with a perfect score of 100 points. Environmental health specialists were required to use a standard form called the Food Official Inspection Report to identify violations as they inspected establishments; the form required them to subtract a certain number of points for each violation found. Based on the number of points remaining, letter grades were then assigned and required to be prominently posted at all establishments selling food, and all establishments were also required to provide a copy of the underlying inspection report to any customer on request. Grades are available at the County Public Health Department's web site. Two Stanford University economics researchers found that higher lettered restaurants scored a rise in revenue, while lower lettered restaurants have seen their revenues decline. The quality of restaurants in the entire county became more acceptable, with the average score going up from about 75% to nearly 90% in the year after restaurant grading was implemented. The researchers concluded that the results were not explained solely by consumers switching to higher quality restaurants, and that some of the effect had to do with restaurants making changes due to grade cards. Another study estimated a 13.1% reduction in hospitalization for food borne illnesses in the year following implementation of the program, suggesting that implementing a restaurant grading program could improve public safety. Although Los Angeles County was not the first local jurisdiction to require restaurants to post grades, its success in implementing such a program inspired many other local governments during the 2000s to enact similar programs based on the Los Angeles model, such as Toronto, Las Vegas, Dallas, and New York City.