The rapid increases of postal rates are excellent indices of inflation, such as the case in China right after WWII. Chinese Nationalist Government, the Kuomintang, tried to stabilize the inflation by changing the monetary systems from the Chinese National Currency (CNC) to Gold Yuan, than to Silver Yuan and the postal rate increases could not be charted on a linear graph paper, even failed to tell the story on a log graph paper. I have tried this numerous times and failed.
The similar economic event happened in Mexico at the end of the Revolution (civil war) in 1916. Nearly one million Mexican were killed. The postal rate changed from 25 centavos on a letter on Sept 1, 1916 to 2 pesos and 50 centavos on Nov 1, 1916. That was 10 time increase in two months.
