Summing hierarchical data SQL

If I have a table or query that returns hierarchical data, how can I sum it? There are counts only at the lowest level and I want to roll it up to the parent levels. Here is an example:

Level	ID	Name	Parent	Frequency
1	1	USA	  NULL
2	2	CA	    1
3	3	LA	    2	       10
3	4	SF	    2	       15
2	5	IL	      1
3	6	Chicago	  5	     5

I want to get this:

Level	ID     Name	Parent	Frequency
1	1	USA	  NULL	  30
2	2	CA	   1	      25
3	3	LA	   2	      10
3	4	SF	   2	      15
2	5	IL	     1	        5
3	6	Chicago	 5	    5