Year	Number of Firms
1997-01-01	1
2004-01-01	4
2007-01-01	1
2008-01-01	3
2009-01-01	1
2010-01-01	1
2011-01-01	4
2012-01-01	4
2014-01-01	3
2015-01-01	2
2016-01-01	3