Year	Number of
1990	162.04
1991	169.07
1992	176.68
1993	185.21
1994	194.28
1995	204.01
1996	215.01
1997	226.52
1998	239.62
1999	253.09
2000	267.24
2001	278.24
2002	290.45
2003	305.58
2004	322.63
2005	342.09
2006	364.75
2007	389.58
2008	414.12
2009	437.87
2010	459.72
2011	476.28
2012	489.09
2013	495.14
2014	504.49
2015	520.61
2016	544.02