Year	Number
1992	12.23404
1993	12.15345
1994	12.11615
1995	12.07387
1996	11.8767
1997	11.96435
1998	12.27635
1999	12.37403
2000	12.0333
2001	12.02536
2002	12.05131
2003	12.12192
2004	11.77706
2005	11.57558
2006	11.6587
2007	11.51158
2008	11.66293
2009	11.6176
2010	11.65385
2011	11.57782
2012	11.56875
2013	12.20682
2014	12.4235
2015	12.35297
2016	12.09753
2017	12.02131
2018	12.03524