Year	Cases per 100,000
1990	1775
1991	1009
1992	749.6
1993	824.8
1994	341.8
1995	82.93
1996	56.77
1997	44.98
1998	46.94
1999	38.03
2000	28.89
2001	26.17
2002	24.14
2003	30.09
2004	24.81
2005	21.7
2006	17.4