Errors like this a embarrassingly common in all sorts of media. Something it looks like genuine errors - charts made by someone who didn't take enough math in school, but more often it's someone who wants to highlight differences of some kind and skews the charts accordingly.

One of the favourite ways of doing this is to make a line chart of two values, maybe mortage rates from two banks, and not make the chart's Y axis based on zero (or put a zero there and make a little squiggle on the line). A minute difference is made to look huge, and it annoys the hell out of me.

I expect things like this in marketing, but what -really- annoys me is when public television does things like this on the news. They really should know better...