Did "et cetera" gain its popularity from "The King and I"?

I searched for et cetera and etcetera in the Corpus of Historical American, and I found the following data:

The chart shows that et cetera was already used before 1956, and its usage has been constant in the period 1950-1960. The usage frequency of the word, in the years between 1950 and 1979, has been 1.47, 1.54, and 3.44 per million, which is lower than the frequency of words like vice versa, and etc., but higher than the frequency of words like et al. and et seq.

While certainly not a good measure of 'everyday speech', the Google Ngrams chart from 1700 to 2000 actually indicates that the highest peaks in literature were in the early 1930s and mid 1940s. You can see a more zoomed in view here.

This would indicate a higher correlation with the 1944 novel Anna and the King of Siam than the movie version. It might also indicate that the novel instead drew on other works rather than being the prime mover.