Clerks of probate courts shall report monthly to the Commissioner of Revenue Services all letters testamentary or of administration granted upon estates of decedents in such courts on forms provided by him for that purpose and containing such information as he may require. They shall also furnish to the commissioner, without charge, a certified copy of every will admitted to probate when they forward the return provided for in section 12-359 for the estate to which such will pertains and, on his written request, such certified copies of any papers on file in such courts pertaining to any decedent‘s estate as he may deem necessary to the performance of his duties.