Rates within Argentina from Ravignani

Based on the book by Miguel Emilio Ravignani about Argentinean postal rates from 1877 to 1974, which luckily includes the complete period of postal use for the Argentina 1935-51 issue these are the rates within Agentina for the three most commonly used rates.

The three main postal rates for mail within Argentina are the simple letter rate (20 grams or approximately 1/2 ounce), the certified mail rate, and the express mail rate.

The simple letter rate for each 20 grams is 10 centavos before 1937, and 5 centavos from 1937 to 1948. The certified and express rates before 1944 are not clear from this book. Here are the rates from 1944 onwards in the format (simple letter rate, certified mail rate, express mail rate):

1944 ( 5 centavos, 25 centavos, 25 centavos )
1949 ( 10 centavos, 30 centavos, 40 centavos )
1951 ( 20 centavos, 60 centavos, 1 peso )
1952 ( 20 centavos, 1.30 pesos, 1.50 pesos )
1956 ( 40 centavos, 2 pesos, 2 pesos )