Year Number 1995 14323566.339892592 1996 16195085.056017153 1997 16782783.74093954 1998 17915072.38730256 1999 19286169.649933685 2000 19581432.375593536 2001 20519199.901892953 2002 22162330.26297617 2003 22926433.429214597 2004 24699148.82510344 2005 26367736.544280343 2006 29762488.241926093 2007 34665318.36968774 2008 35737670.05606499 2009 36704327.02142125 2010 40334502.46257172 2011 40741755.28480565 2012 43202323.0203332 2013 44728989.89684981 2014 46510985.555116385 2015 48979055.51012856 2016 51223036.38285962 2017 52899581.205879405 2018 56673405.06535894 2019 56014499.15394769