2006 – 3,990 total observations 2007 – 8,490 total observations 2008 – 6,838 total observations 2009 – 15,300 total observations 2010 – 17,805 total observations 2011 – 14,249 total observations 2012 – 16,848 total observations 2013 – 14,879 total observations 2014 – 18,506 total observations