I am part way through The Leading Indicators: A Short History of the Numbers that Rule Our World. The book essentially argues that modern economics came to being in the 1930/40s. If you go to Ngram which is a Google generated search engine which shows you the number of words in all their digitized books and based on the book Unchartered, you can see that indeed there is a noticeable jump in the words "the economy" starting in 1940. Likewise economics as a discipline came into vogue in the 19th century and true to form you can see it increasing dramatically in book mentions starting with the 1880s.
Plugging in words and phrases actually is a fun exercise for you and your students.