Year	Number of
1990	129.19
1991	142.2
1992	155.85
1993	167.48
1994	185.26
1995	202.81
1996	216.85
1997	227.11
1998	237.65
1999	239.74
2000	237.24
2001	234.49
2002	228.74
2003	228.1
2004	217.55
2005	212.02
2006	208.79
2007	203.33
2008	198.16
2009	195.26
2010	192.7
2011	190.06
2012	186.79
2013	184.44
2014	181.44
2015	181.43
2016	183.64