How do I count net work days by year?

[paulcardenas]

Hi there,
Let me say first thank you in advance for any help!
I need to determine which employees at my work are eligible for a bump from 2 weeks vacation to 3 weeks vacation per year. I understand the net work days function but the problem is the rehire and layoff dates often cross years and I need to determine how many net work days by year.
Here's the rule for determining eligibility: employee needs 100 net work days per year for seven consecutive years to be eligible for 3 weeks vacation. Once eligible, they must have 150 net work days per year to maintain eligibility.
Here's what the data looks like:

NEW HIRE	7/15/96		Year	net work days
LAY OFF	4/15/97		1996	# of days
REHIRE	6/16/97		1997	# of days
LAY OFF	5/1/98		1998	# of days
REHIRE	6/22/98		1999	# of days
LAY OFF	5/14/99		2000	# of days
REHIRE	7/5/99		2001	# of days
LAY OFF	5/4/01		2002	# of days
REHIRE	8/6/01		2003	# of days
LAY OFF	6/14/02		2004	# of days
REHIRE	6/14/02		2005	# of days
LAY OFF	5/23/03		2006	# of days
REHIRE	7/21/03		2007	# of days
LAY OFF	5/26/04		2008	# of days
REHIRE	8/16/04
LAY OFF	5/25/05
REHIRE	7/25/05
LAY OFF	5/24/06
REHIRE	7/17/06
LAY OFF	3/11/08
REHIRE	4/2/08
LAY OFF	7/3/08
REHIRE	8/25/08
LAY OFF	9/19/08

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