Google plots popularity of favored Carolinas terms

If you haven't tried the Google Ngram Viewer, you're missing out on a word-geek treat. Its a database of all the words in five million books published since the 16th century. You can plug words or phrases in and get a chart showing how popularity of the word waxes and wanes over the centuries. I plugged in a bunch of Carolinas words just to see what happens. Here's what I found:

• Piedmont -- Except for one surge around 1670 (the year English settlers landed at Charleston), the word was virtually invisible until the 1880s. Usage reached its highest level in the 1940s, and has fallen since then.
• Carolina -- Usage surged briefly around 1670, but began rising dramatically around the time of the Civil War. After about 1940, it trended generally downward until the 1980s, when it rose moderately again.
• Moonshine -- Perhaps not surprisingly, usage zips upward around 1919, when the Prohibition era began.
• Fish camp -- Not used much until the 20th century. Usage spiked around 2000.
• Tarheel -- First came into print in the late 19th century; usage increased dramatically after 1920.
• Barbecue -- First crept into print around 1750, but didn't gather steady momentum until about a century later. Usage gradually increased until the 1980s, when it skyrocketed.

Why do you think these words took off in print when they did? Got any other good Carolina words you'd want to plug in?