We can mention five emerging periods: P 1 (1916–1922) the joint entropy S and the mutual information I stay approximately constant; P 2 (1922–1937) the S takes a leap up and then stabilizes, while I reveals a slight increase, with some oscillation, and then stabilizes; P 3 (1937–1945) the value of S increases and I decreases; P 4 (1946–1956) the S decreases considerable and reaches a new local minimum, while the value of I remains approximately constant; P 5 (1956–1970) the value of S reveals an increasing trend, while I changes only a little bit, revealing a slight increase just at the end of the period.
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