Highly recommended using www.coppercoins.com or www.lincolncentresource.com What you have there is what appears (me) to be a form of die detoriation or possibly plate split doubling having trouble with that picture. Wish it could be a DDO because that would be the first that I seen for that year
1991 was a terrible year for pennies. Judging from the prox 20,000 pennies I've sorted (and I suspect those with 6 figures under their belt will back me up) a very high percentage had plate splits on the final "1". Another high percentage have grease filled die on he final "1", and I've seen more than a few where the final "1" has literally broken off in Post Mint Damage. I've seen it on P and D coins, so it's something about the dies not being completely level, I think. Because of this the final "1" is a stress point, and BSH (Bad ummm...Stuff Happens).
