Pepsi drawing of vintage bottles limited edition numbered

[ChuckyBoy]

Hi, I am looking for information on a  1991 numbered limited edition drawing of 6 vintage Pepsi Bottles by artist Mary Williams, number 21 of 250. The drawing depicts 6 Pepsi bottles 1907 to 1979.  The frame measures approx. 31 in X 16 in. I inherited it from my brother who worked in Pepsico marketing.
Thank you,
Chuck