I have been doing more research and came across this. I found it on a legal site that is fee based and in it you will read some arguments that have been posted here by several posters. Anyway, I wanted to post this so anyone interested could read it:

So while statistics may indicate that pit bulls are responsible for a given number of bites, the bites could have been inflicted by any combination of the three breeds, pit-bull dominant mixes, or one of the more than twenty-five breeds commonly mistaken for a pit bull.

Second, statistics may not accurately convey the danger posed by a particular breed because of the “floating numerator” problem. Ideally, bite rates could quantify the relative dangerousness of certain breeds by comparing bites to breed. In other words, the numerator would be the number of dog bites or canine homicides per breed and the denominator the total number of the breed in the general canine population. As a 2000 study stated, “[ten] fatal attacks by Breed X relative to a population of 10,000 X's (1/1,000) implies a greater risk than 100 attacks by Breed Y relative to a population of 1,000,000 Y's (0.1/1,000).” However, many dogs are unregistered or unlicensed, making it difficult--if not impossible--to properly ascertain the population of a given breed. The problem inherent in the current method of statistical analysis can be illustrated in this way: A report of five bites by Akitas and ten by pit bulls suggests that pit bulls are the more dangerous breed. If there are only ten Akitas in the canine population and one hundred pit bulls, however, it becomes clear that pit bulls in fact pose the lesser public threat.

Enforcement Costs

Many cities have repealed breed-specific legislation due to enforcement costs, which can be prohibitively high. Direct costs of breed-based regulations and bans include additional animal control staff necessary for enforcement of the law, kenneling both for dogs awaiting a determination of breed and for dogs whose owners appeal such determinations, and veterinary care for kenneled dogs. Direct costs also include the legal expenses the city must pay, such as attorneys' fees and court costs, to defend its law against constitutional challenges. Indirect costs may include loss of city revenue, as the ban could affect the number of or attendance at dog shows or exhibits held in the county, and inhabitants, as owners may move outside city limits to protect their dogs.

In 2003, Prince George's County, Maryland, formed a task force to “evaluate the effectiveness” of its vicious animal legislation, including its pit bull ban, and make recommendations for improvements and amendments. The task force recommended repealing the ban and strengthening the city's dangerous-dog law. The recommendation was based on numerous cost concerns: (1) The cost of maintaining a single pit bull throughout the entire determination and appeals process was approximately $68,000; (2) fees from pit bull registrations over a two year period generated only $35,000 while the cost to the Animal Management Division for maintenance of pit bulls over the same period was about $560,000; and (3) the costs did not include expenditures such as payroll, cross-agency costs, and utilities.

Impact on Public Safety

Breed-based regulations and bans are frequently enacted following a highly publicized dog attack and typically target the breed involved in the attack. These legislative enactments are designed in part to alleviate public fear and provide a feeling of security. However, that feeling of security may be false. Unless a dog subject to a breed-based ordinance is registered, spotted by law enforcement officials or neighbors, or voluntarily turned in by the owner, enforcement is difficult. Further, there is no guarantee that owners will abide by the law. In 2002, authorities estimated that in Miami-Dade County, Florida, which enacted a pit bull ban in 1988, approximately 50,000 pit bulls remained in the county illegally. In Denver, which reenacted its pit bull ban in 2005, pit bull owners hide their dogs to avoid seizure and destruction.

It is also not clear that breed-specific legislation has any impact on public safety. Although the United Kingdom has prohibited the sale and breeding of pit bulls since 1991, the law has had no impact on the number of dog attacks. Moreover, even if one breed is banned, owners who desire vicious dogs can circumvent the law by breeding and/or training a new vicious breed. After Diane Whipple's death, for example, a number of Presa Canario breeders received calls from potential owners wanting “‘that dog that would kill.”’ As dog-bite law expert and attorney Kenneth Phillips states, “‘Any dog--literally any dog--can be a bad dog if the owner is a bad owner or the breeder is a bad breeder.”’