Well, that was just "in". The Soviet Union, in the
late 60s, operated:
with internal guns
1000 MiG-17 -> fighter (initial:
1952)
350 MiG-19 -> fighter (initial:
1955)
200 Yak-25 -> interceptor (initial:
1955)
without internal guns
750 Su-9 -> interceptor (initial:
1959)
350 Yak-28 -> interceptor (initial:
1960)
150 Tu-28 -> interceptor (initial:
1963)
400 Su-15 -> interceptor (initial:
1967)
Notice something?
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Numbers:
CRS US/Soviet Military Balance, Statistical Trends, 1970-1980; stats for 1970