- Opinions in 1980 were published in the official Opinion Book in alphabetical order by subject matter, rather than date issued; therefore the opinion number relates to the 1st page of the opinion by page number of the hard-copy opinion book.
- Opinion numbers for 1981 - 1992 have been numbered to reflect the date order in which the opinion was issued.
- In 1993, the Office of Attorney General adopted a "Letter" or "Formal" designation for opinions. For the years 1993-2000 (inclusive), Formal Opinions were numbered consecutively as issued (in date order). Letter opinions have an opinion number based on the page number for the 1st page of the opinion in the official (published) Opinion Book for that year.
- The original numbering systems have been maintained because later Opinions cite to the opinion number used at that time (i.e. the page number in the Opinion Book on which the opinion started).
- In 1997, the Office of Attorney General added "Open Records/Open Meetings" opinions, using "O" in the numbering (2001-O-05) to differentiate those opinions from Letter & Formal opinions. All Open Record/Open Meeting opinions are in a separate (searchable) opinion bank.
- In June 2003, the "Formal" designation was dropped; all opinions issued thereafter are "Letter" opinions, numbered consecutively as issued.