This is the data I have :

Code:
HIER_LEVEL  STANDARD_SOURCE	TITLE	                 YEAR_ADOPTED	
1	     FL	                  Sunshine State Standards	2006	
1	     FL	                  Sunshine State Standards	2007	
1	     GA	                  Performance Standards	        2004	
1	     GA	                  Performance Standards	        2004
And this is the output I need :

Code:
HIER_LEVEL  STANDARD_SOURCE	TITLE	                 YEAR_ADOPTED	  GROUP_ID
1	     FL	                  Sunshine State Standards	2006	1
1	     FL	                  Sunshine State Standards	2007    2
1	     GA	                  Performance Standards	        2004      3
1	     GA	                  Performance Standards	        2004      3
But I am not able to write the correct query. I am using ROW_NUMBER () function. Any other suggestions ?