My Dear

I noticed that the Virginia A.G.'s 1989 opinion on residential picketing began with "My Dear Mr. Godfrey:"—the opinion was a response to Washington County Commonwealth's Attorney Dennis Godfrey—and it made me wonder: How long had the "My Dear" salutation (as opposed to just "Dear") endured?

It appears that, true to Virginia's genteel Southern image, the Virginia A.G.'s office did use "My Dear …" as a salutation until 1996, well beyond any other state office (e.g., the Iowa A.G.'s office, which kept it up until 1965). But the U.S. Justice Department's Office of Legal Counsel used "My Dear Mr. President" until as late as 1999, under Janet Reno.

UPDATE: Joshua J. Prince (@JoshuaJPrince) notes that Justice Kennedy opened his retirement letter with "My dear Mr. President"; I expect some other similarly individual letters, rather than institutional ones, might continue using that salutation.