year | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 |
corp | 501,234 | 493,240 | 471,582 | 467,672 | 438,733 | 411,798 | 399,955 | 390,147 | 377,692 |