Here is Ismael Kirui's (Ken) progression up to and including 1993:
YEAR AGE 5000 m 10,000 m
1990 15 13:59.6 28:40.77
1991 16 - -
1992 17 13:15.67 29:35.0
1993 18 13:02.75 28:07.1
Haile Gebrselassie (Eth)
YEAR AGE 5000 m 10,000 m
1992 19 13:36.06 28:03.99
1993 20 13:03.17 27:30.17
William Sigei (Ken)
YEAR AGE 5000 m 10,000 m
1989 20 13:44.6 -
1990 21 - -
1991 22 13:56.3 -
1992 23 13:15.01 28:35.0
1993 24 13:07.35 27:16.81
Salah Hissou (Mor)
YEAR AGE 5000 m 10,000 m
1989 17 14:15.0 -
1990 18 14:05.9 -
1991 19 13:37.40 -
1992 20 13:41.55 28:31.62
1993 21 13:49.5 -
1994 22 13:04.93 27:21.75
1995 23 13:02.25 27:09.30
1996 24 12:50.80 26:38.08