18,852
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
11,689
1990
12,194
1991
12,401
1992
12,841
1993
13,677
1994
14,211
1995
14,374
1996
14,678
1997
14,117
1998
14,371
1999
15,230
2000
15,930
2001
16,302
2002
16,703
2003
16,500
2004
16,481
2005
16,759
2006
16,660
2007
16,700
2008
17,208
2009
17,368
2010
17,969
2011
18,405
2012
18,667
2013
19,083
2014
18,878
2015
18,852
2016
