Year	Number of
1990	97.4
1991	100.42
1992	103.93
1993	107.83
1994	112.15
1995	116.89
1996	124.37
1997	132.58
1998	141.64
1999	151.45
2000	162.09
2001	165.6
2002	169.35
2003	174.12
2004	179.37
2005	185.33
2006	193.16
2007	201.95
2008	211.51
2009	222.48
2010	235.35
2011	246.28
2012	258.18
2013	270.17
2014	281.19
2015	290.89
2016	302.08