Year Number 1996 3514.48 1997 3905.61 1998 4342.56 1999 3982.13 2000 4411.53 2001 4347.95 2002 4628.75 2003 4636.83 2004 4857.73 2005 5572.92 2006 5566.75 2007 5841.51 2008 6432.62 2009 5998.04 2010 5891.47 2011 6395.73 2012 6445.62 2013 6211.44 2014 6611.54 2015 6524.89 2016 6425.46 2017 6646.45 2018 6684.52 2019 7129.81 2020 7478.17