Soviet union combat aircraft numbers in 1989?

I’ve been trying to add up all the tactical combat aeroplanes (fighters, attackers, interceptors, etc) in active service in soviet union at the end of cold war, say end of 1989.

It’s pretty hard to find even decent sources so all of my figures are rather rough, but perhaps you people can point me in a better direction. Most often i started with total numbers produced per type, substracting numbers produced for export or other warsaw pact countries, then trying to guesstimate how many would have been retired and replaced by a new type in a given year.

I did not take into account attrition, be it from regular mishaps or combat induced losses (afghanistan, etc). i am sure total numbers should be a bit lower still due to those. 1-3% per total fleet numbers at a given year per number of years in service?

Anyway, here’s what i got so far. Please correct me where possible.

6-8 thousand mig-21
230 yak-38
550 yak-28
900 mig-27
2300 su-17
1300 su-24
580 su-25
5000 mig-23
1000 mig-25
1000 mig-29
500 mig-31
1000 su-15
650 su-27
100 tu-128

Could someone help me with mig-21 in particular? how many hours-in-air was the airframe used in Soviet union? how many years did an average mig-21 serve back then, before retirement? is the 7000 active airframes a realistic figure for end of 1989?

As an addition, approximate totals of other warsaw pact countries in 1989 seem to be:

300 mig-23 (i had to guess czechoslovakia’s numbers, couldn’t find any sources for that one)
80 mig-29
8 mig-25 ?
220 su-22
95 su-25
1700 mig-21
100 su-7 ??
10-20 mig-17 ??