see also the ngram viewer: https://books.google.com/ngrams/graph?content=conspiracy+theory&year_start=1900&year_end=2018&corpus=15&smoothing=3&share=&direct_url

see also the ngram viewer: https://books.google.com/ngrams/graph?content=conspiracy+theory&year_start=1900&year_end=2018&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Cconspiracy%20theory%3B%2Cc0 https://books.google.com/ngrams/graph?content=conspiracy+the...