Year Number 1995 11583544.705829557 1996 13088654.204097895 1997 13456245.973343946 1998 14403851.832546368 1999 15309377.842034195 2000 15353177.301304992 2001 15854696.28600283 2002 17383375.415747426 2003 17844385.282023642 2004 18745951.162755266 2005 19917566.3729011 2006 22650320.879912134 2007 25114898.436753795 2008 25413098.26745147 2009 25964418.069538254 2010 29071500.511440605 2011 31650243.884142708 2012 32748552.390675176 2013 34426632.679692656 2014 35738392.214013554 2015 35318681.46454987 2016 37645887.77446596 2017 38258347.87559703 2018 41189145.26870986 2019 39826701.40254885