Year Number 1998 9.39264 1999 9.90644 2000 9.69221 2001 9.90224 2002 10.14622 2003 9.82366 2004 9.66316 2005 9.69107 2014 8.70334 2015 8.35042 2016 8.04983 2017 8.19168 2018 7.77961