Year	Number of
1990	104.99
1991	110.44
1992	115.98
1993	122.75
1994	130.79
1995	139.66
1996	148.63
1997	159.03
1998	173.29
1999	186.91
2000	193.86
2001	199.46
2002	202.34
2003	205.73
2004	206.51
2005	210.7
2006	211.68
2007	212.84
2008	215.03
2009	215.56
2010	213.32
2011	214.22
2012	212.76
2013	205.72
2014	199.49
2015	195.39
2016	193.85