It does not take much visual comprehension to see the correlation between witchcraft and yoga on the Google Ngram chart below. Although Google’s Ngram viewer only tabulates the instance of words in books in its database, it is still a proxy for seeing trends in the public’s interest in particular topics. You cannot equate Ngram studies to the descriptive power of longitudinal scientific surveys. However, surveys reflect attitudes not actual behavior, and publishers tend to market books that the public will buy.
What is most interesting are the inflection points of the lines in the graph. The incidence of the term witchcraft tends to change direction before yoga. You can see this from the period of the mid-1960’s and from late 1980’s to the mid-1990s. Interest in astrology tracks more directly with yoga. You might expect to see this relationship between yoga and astrology in India where all things spiritual and divinatory are popular, but this graph is only of books in American English.
What is most interesting is the beginning of the downward trend in the late 2000s just as Christian Yoga began its boom, but the modern evangelical church has always been trend chasing. Why don’t they all become just Episcopalians and jump ahead of the curve?