Year	Number of
1990	38.5
1991	40.03
1992	41.74
1993	43.63
1994	45.53
1995	47.57
1996	49.5
1997	51.71
1998	54.02
1999	56.5
2000	59.16
2001	60.88
2002	62.76
2003	64.89
2004	67.07
2005	69.37
2006	72.29
2007	76.25
2008	80.28
2009	83.91
2010	87.45
2011	90.47
2012	94.41
2013	97.89
2014	101.35
2015	105.44
2016	109.69