Year Number 1993 21.55081 1994 19.85 1995 19.89325 1996 20.0836 1999 23.72564 2000 21.71065 2001 27.20557 2003 28.10908 2008 29.81904 2010 24.76389 2011 23.03909 2012 22.72188 2013 22.90667 2014 23.00687 2015 22.79732 2016 23.53968 2017 24.16483 2019 24.86179