Basically, sugar did not increase in price over that time span - except for a dramatic spike around world war I and relatively minor fluctuations.
That spike put Pepsi into bankruptcy, the company was sold at auction, reorganized, and after the great depression started selling a DOUBLE-SIZE (12oz) bottle for ... wait for it... $0.05).
There are other costs (production, distribution) but over that time period, those were benefiting from decreased cost through industrialization, etc.
This link gives a history of the sugar price (only back until 1912): http://www.tradingeconomics.com/commodity/sugar
Basically, sugar did not increase in price over that time span - except for a dramatic spike around world war I and relatively minor fluctuations.
That spike put Pepsi into bankruptcy, the company was sold at auction, reorganized, and after the great depression started selling a DOUBLE-SIZE (12oz) bottle for ... wait for it... $0.05).
http://suite101.com/article/soda-pops-of-the-1800s-1900s-20s...