Year	Number of
1990	204.61
1991	209.86
1992	212.93
1993	219.02
1994	221.31
1995	226.83
1996	229.4
1997	226
1998	229.96
1999	228.51
2000	227.12
2001	226.98
2002	223.02
2003	219.38
2004	221.31
2005	217.95
2006	214.28
2007	211.41
2008	217.6
2009	221.4
2010	227.55
2011	229.5
2012	237.73
2013	241.23
2014	244.24
2015	250.64
2016	256.37