[size=12.800000190734863px]Hello I'm working on some project and need to count number of events between any of two event dates for each firm. I have data look like this:

event date	firm cusip	number of event +/- 183 days	number of events +/-365 days	number of event +/- 548 days
1991/2/21	21
1992/3/24	21
1994/3/7	361
1997/6/10	361
1998/9/9	361
2000/1/11	361
2009/6/15	361
1996/8/2	375
1997/1/23	375
1998/3/24	375
1999/7/21	375
1999/8/26	375
1999/11/28	375
2000/1/13	375
2000/5/8	375
2000/6/15	375
2000/6/30	375
2000/7/4	375
2000/7/6	375
2000/9/25	375
2000/10/5	375
2000/10/16	375
2001/2/19	375
2004/4/1	375
2005/6/22	375
2005/12/20	375
2007/6/14	375
2008/4/16	375
2008/8/22	375
2008/10/23	375
2009/3/31	375
2009/12/10	375
2011/6/12	375
2011/8/1	375
2012/3/6	375
2013/5/7	375

[size=12.800000190734863px]For column named number of event +/- , I need to count, for the same firm, number of event dates within the range of [-183,+183], [-365,+365],[-548,+548] relative to the event date on the same row. So for example, for firm with cusip=21, there are 397 days between two event date, 1991/2/21 and 1992/3/24, so in the first row, there are 0 event within the range of [-183,+183] relative to 1991/2/21, but there are 1 event within the range of  [-365,+365], and 1 event within the range of [-548,+548]. In the second row, I need to count the number of event for the same firm within these three ranges relative to the date of 1992/3/24. I need to do the same for three firms. This is the first time I do this kind of counting staff and I tried several method but they do not work on all of the firms. Please help!!