Year	Number of
1990	214.69
1991	212.42
1992	213.69
1993	214.97
1994	216.87
1995	216.75
1996	215.71
1997	213.61
1998	205.06
1999	200.41
2000	194.83
2001	191.01
2002	186.22
2003	176.45
2004	173.72
2005	173.45
2006	174.92
2007	178.84
2008	181.65
2009	189.34
2010	198.08
2011	203.79
2012	203.65
2013	206.94
2014	215.97
2015	218.22
2016	222.27