Office of Personnel Management website has provided an annuity statement rather than a 1099R. How do enter this retirement income on my tax return if it is not a 1099R?

You need to get a 1099-R or CSA-1099R from OPM for your tax return.

According to the OPM website (OPM.gov), you can use Services Online (Retirement Services) to request a duplicate tax-filing statement (1099R).

I get a CSA 1099R myself and it can be downloaded from the web site.  

Thanks. Confused because download form does not have the same boxes as listed in TT, and dropdown list does not include needed nondisability distribution code. Will go with form as downloaded.

Turbotax says copy information exactly as shown on 1099-R except for corrections, but can't do since TT and 1099 don't match in many boxes - confusing.

Make sure when you enter the CSA 1099R or CSF 1099R at the beginning you mark what type of 1099R you have.