Year Number of Firms 1997-01-01 4 2002-01-01 4 2004-01-01 1 2006-01-01 3 2007-01-01 2 2009-01-01 2 2010-01-01 4 2011-01-01 1 2013-01-01 1 2014-01-01 3 2015-01-01 7 2016-01-01 4