Ahodges/doc/doc1119

@shnayder @WatsonEmily @dsjen @srpearce @stroilova here's the initial draft for the gender demographic data. I don't have access to real data yet, so can't quite finish up the screen-shot-and-its-interpretation piece. (Suggestions on a good illustration welcome)
"Columns show each date, the total enrollment on that date, and..."

or

"The file has a **Date** column, a **Total Enrollment** column, and breakdown columns..."