Year	Number of
1990	104.67
1991	107.47
1992	109.76
1993	111.45
1994	116.36
1995	121.94
1996	131.4
1997	132.54
1998	141.63
1999	146.77
2000	153.76
2001	162.17
2002	170.71
2003	181.42
2004	194.57
2005	207.98
2006	221.51
2007	230.56
2008	240.44
2009	250.19
2010	255.58
2011	262.02
2012	271.41
2013	276
2014	281.43
2015	285.96
2016	290.95