Just googled "G-7 conference" and found a reference to the 1996 event. The nations listed were U.S., Britain, France, Canada, Italy, Germany and Japan. (I'd post the link but am basically computer-illiterate and don't know how to do it ). Googling G-8 produced references to the 1999 and 2000 conferences....so using my amazing powers of deduction ....it seems Russia was added in 1997 or 1998.