Year	Number of
1990	131.31
1991	135.7
1992	140.42
1993	145.42
1994	150.75
1995	156.45
1996	162.52
1997	169.06
1998	176.06
1999	183.62
2000	191.81
2001	198.79
2002	206.33
2003	214.45
2004	223.21
2005	232.74
2006	242.33
2007	252.65
2008	263.93
2009	276.07
2010	289.21
2011	301.61
2012	315.05
2013	329.47
2014	344.88
2015	361.31
2016	378.15