The bar chart compares the number of cases over time. The average in the 1996–2002 period was over 40 cases per year. This jumped in 2003 to 130 cases, and peaked in 2004 at almost 140 cases. It dropped somewhat to almost 100 cases in 2005, and dropped further still to 70 cases in 2006. The number of cases began to climb in 2007, to more than 80 that year, and exceeded 100 in 2008. The number of cases for 2009 was 80, although this number could have changed because it was set as of December 16.