6 ozs (170 grams)
Well I know for a fact that that exact brand of Tuna was $0.50 in 2008 ( used to eat tuna and crackers for breakfast several times a week back then) and is now $0.95 at the same store I bought it from back then.
If we calculate 6 oz/0.50 vs 5 0z/0.95, I believe we will discover that the increase in cost is 2.28 times, meaning over 100%.
Also this web page confirms the price at over $1.00 per can. (You have to attempt to buy it. They sell a 24 pack for $26.74.)