Year % net 1992 16.60082 1993 16.63517 1994 16.83279 1995 17.07103 1996 16.98697 1997 16.89631 1998 17.24552 1999 17.49563 2000 18.21793 2001 19.08439 2002 19.95081 2003 20.95861 2004 22.32802 2005 23.10283 2006 23.89674 2007 24.44371 2008 26.63833 2009 28.33974 2010 30.06803 2011 30.25196 2012 30.51339 2013 31.63519 2014 32.22259 2015 32.96741 2016 33.74958 2017 34.67489 2018 35.01341