Grading distraction: Google's NGram Viewer on mentions of social work, social workers

Yesterday, Google Book's NGram Viewer was discussed on WBUR....click here for more info, but above please find a chart I generated just now (while procrastinating on the last few bits of grading).  Why the spike in mentions of social work and social workers in the late 90s? 

NOTE: CLICK ON CHART TO SEE FULL VERSION

What uses can you think of for this interesting new tool?

Here is the blurb on the program from yesterday and a bit on the tool itself...

Trending Terms, Digital Books & Historical Data Crunching

We look at what 500 years of word usage tells us about our culture. See the Google Books Ngram Viewer.

We are the species of language and words. The words we use come pretty close to defining us … the way we see the world. And those words change over time — dramatically.

Now, researchers are tapping a massive new database of words and phrases from 5 million books to see how our embrace and use of words has changed over centuries.

Google put it up. The new tool lets you map the path of any word through time. “Beseech”? It’s way past its prime. “God”? That word peaked in 1830. “Twitter”? It was huge in 1900, and coming back, changed.
We look at our history, and life, in words. 

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Also, check out this chart of disability-related terminology...applications for my disability policy and practice course...