Year	Number
1991	5101924
1992	5228015
1993	5634662
1994	5783786
1995	5891319
1996	5986050
1997	6061870
1998	6390693
1999	6455170
2000	6571431
2001	6647052
2002	6711741
2003	6716720
2004	6590637
2005	6477468
2006	6371619
2007	6255188
2008	6165863
2009	6158257
2010	6106595
2011	6070384
2012	5996583
2013	5950879.20683
2014	5852544.86526
2015	5791963.34125
2016	5721174.29372
2017	5680849.44367