I agree with the earlier post that "many" was probably more appropriate
than "Most".

As to when "many" lost there currency usually it is with 6 months to a
year after their insturment check ride. The next time I was IFR
Current was 6 years later when a week after my CFII Check ride I went
for an IFR Proficency flight with my instructor. Interesting according
to my Examiner the CFII Checkride did not qualify for Instrument
Proficency unless the Examiner signed it off as such.

Brian