Combined, these four states accounted for 49.2 percent of all TB cases in the country last year. In 2008, TB rates ranged from 0.5 per 100,000 in North Dakota to 9.6 per 100,000 in Hawaii, the study said. However, the CDC report also noted that progress in eliminating tuberculosis has slo in recent years, with a 3.8 percent average annual rate of decline between 2000 and 2008, compared with a 7.3 percent rate of decline from 1993 to 2000. Centers for Disease Control and Prevention reported 12,898 new cases of TB in 2008, which equals 4.2 cases per 100,000 people.

Although 33 states and the District of Columbia reported lower rates in 2008 than in 2007, 17 states had higher rates. Four states -- California, Florida, New York and Texas -- reported more than 500 TB cases each in 2008. -- Tuberculosis cases reached an all-time low rate in the United States last year, according to a new federal government report.

In 2007, five states had at least 500 cases, and seven states recorded that many in 2006.