post office statistics

Did you know that there have been a few times in the past when the cost of mailing a letter has actually decreased?

Historical USPS statistics

Yes, apparently the cost of mailing a letter decreased from 3 cents to 2 cents (per once) in 1919. That translates to approximately a 3.44% yearly increase to the current value of 42 cents. From the 33 cent cost in 1999 the increase has only been 2.5%. Can we assume from this that the cost of mailing letters has decreased? Now that we're getting close to a state of deflation, will the USPS lower prices again? Well, apparently that's not on their plan given that their financial situation is not very healthy. What they are considering is cutting delivery back to 5 days a week.

The number of delivery days doesn't seem to me like a big deal... assuming the number of days for the letter to get there remains unchanged.