Year	Number of
1990	131.23
1991	139.13
1992	146.18
1993	153.47
1994	161.51
1995	170.1
1996	179.19
1997	188.69
1998	199.44
1999	209.33
2000	218.95
2001	227.48
2002	236.05
2003	246.65
2004	257.21
2005	268.12
2006	278.63
2007	289.32
2008	301.44
2009	313.91
2010	326.43
2011	338.55
2012	350.93
2013	363.46
2014	377.04
2015	391.42
2016	406.86