Timeline for all types of items produced by
GPA

Year	Items
1987	3
1988	5
1989	12
1990	9
1991	5
1992	7
1993	3
1994	1
1995	1
1996	1
2002	1
2003	1
2004	1
2005	1
2008	1
2009	1

53 items with a valid date were considered for this timeline (67.09% of the total)
26 items with an invalid date.

Help us in our quest to find exact dates for:

199?: 14 items.
19??: 11 items.
200?: 1 item.