Year	Number of
1990	17633.34
1991	18343.42
1992	19029.99
1993	19691.65
1994	20389.89
1995	21168.43
1996	21761.81
1997	22360.59
1998	22974.58
1999	23589.86
2000	24226.64
2001	24680.22
2002	25131.35
2003	25602.66
2004	26117.67
2005	26691.74
2006	27210.13
2007	27725.37
2008	28227.7
2009	28733.75
2010	29262.4
2011	29493.93
2012	29770.73
2013	30092.5
2014	30416.84
2015	30743.64
2016	31077.72