Standard and common focal length lenses comprised 90% of copies (table).
After 50-60 yrs. many surviving/preserved lenses are used and traded keenly, especially pre-1965 types; relative to production estimates.
Frequency lists in Takumar Field Guide suggest that all standard models from 1966 forward (see green shading) are numerically under-represented in current markets.
This result is hardly surprising given the popularity of Asahi Pentax cameras among amateur photographers and world-class lens-making skills shown by employees of the Asahi Optical Company in the period.
What about the future? By 2020 when sample size exceeds 50K (?) an emphasis on serial numbers will give way to other interests.
Presently, Takumar Field Guide sample size is 48,200 copies. It is estimated 7,677,300 copies in 4,937 identified batches were produced.
The last batch (Super-Multi-Coated TAKUMAR 28mm) was completed in 1980 with its last observed lens SN 8419613.
Expansion of the P67 Field Guide continues. From 1969 to 1975 approximately 350K (TAKUMAR and PENTAX) 6x7 lenses were made.