Since everyone was more interested in חֲנֻכָּה, than Halakhah or Kabbalah, here is the chart. I started with all 13 possible spelling and kept the ones that moved off the bottom axis. Here we have two major contenders since the 1930’s. No major change from the EJ in the 1970’s. The question is what happened in 1930 to change the preferred spelling from Ch to H. And what happened to make Channukah with two n’s the preferred spelling of the 1940’s. Click on Chart to enlarge.
The Book of Doctrines and Opinions: 
Oddly, someone else got a different result for the same search. I haven’t played around with Ngrams enough to understand.
http://www.tabletmag.com/scroll/53877/a-short-history-of-words/
I did not use hanukah. It was not on the random list I found.
I dont know why are blue and red lines are not the same. There are a number of variables to set- but I am not sure what they all do. It is a new toy.