Year	Number of
1990	101.72
1991	105.56
1992	109.61
1993	113.82
1994	118.21
1995	122.93
1996	126.59
1997	130.61
1998	134.85
1999	139.15
2000	143.57
2001	146.21
2002	148.75
2003	151.35
2004	154.2
2005	157.57
2006	161.11
2007	164.87
2008	169.16
2009	173.82
2010	178.98
2011	183.39
2012	188.46
2013	193.85
2014	199.61
2015	205.73
2016	212.58