Year	Number of Firms
1997-01-01	2
2002-01-01	4
2003-01-01	3
2004-01-01	3
2005-01-01	3
2006-01-01	7
2007-01-01	7
2008-01-01	5
2009-01-01	4
2010-01-01	7
2011-01-01	5