Chart of the Day: Why Black Friday matters

Don't see the point of Black Friday? Can't understand why people would line up for hours in the cold for a TV?

Well, for retailers, it matters. A lot.

Over the last three years, Black Friday sales have accounted for anywhere from 51 percent to 56 percent of all holiday season sales, according to per-person spending estimates from the National Retail Federation.

Not many businesses can say they do more than half their season's sales in one day.