"Sir F.A. Rien" wrote in message
...

The postal increase of November 2, 1917 and of July 6, 1932 were 50%
jumps.

Yes indeed, but...

The increase couldn't be smaller in 2017 because the rate jumped from $ 0.02
to $ 0.03. The $ 0.01 (or 1 cent, penny) was and is the smallest subdivision
(coin) of the dollar. BTW, this rate dropped just after two years (the end
of war) back to $ 0.02.

The same is valid for the 1932 increase, just that the rate didn't drop back
anymore. Some following increases were also significative in percents, but
the 6 to 8, 10 to 13 etc. weren't the only alternative increases anymore.

Anyway, the last increase on Jan. 27, 2019, a 10 percent jump since Jan. 21,
2018, is a very important one and shouldn't be underestimated.

https://en.wikipedia.org/wiki/Histor..._postage_rates

Let us compare the last increase in postal rate with the general inflation
rate: "Annual inflation rate in the United States fell to 1.9 percent in
December of 2018 from 2.2 percent in November, matching market expectations.
It is the lowest inflation rate since August of 2017 (...)".

https://tradingeconomics.com/united-.../inflation-cpi

Therefore roughly over the last year the USPS postal rates went up 10
percent while the inflation actually went down. I mentioned the inflation
because it was the usual "culprit" for postal rates increases, even if it
grew significantly slower.