Year	Number of Firms
1992-01-01	12
1997-01-01	11
2002-01-01	20
2003-01-01	23
2004-01-01	21
2006-01-01	2
2007-01-01	3
2008-01-01	1
2009-01-01	2
2010-01-01	3
2011-01-01	1