| Year | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 (Jan.) |
| Number | 53,168 | 64,687 | 98,190 | 116,454 | 124,230 | 119,538 | 63,233 | 61,052 | 5152 |