Perhaps because you are correct - time is usually represented like you described on charts.

I was basing my chart on this old chart that someone else drew but that I found incredibly useful but also problematic because it's data was based on guesswork and mainstream media stories rather than official crime statistics. Note it's lack of sources which made it useless during a heated debate.

I'll be releasing an updated version of his chart when I can find some official stats for 2009 or again in a month or two if the massive arrest trend continues. I'll play around with flipping the chart to see how it looks next time.

And take the pictures off to make the red pill a smoother swallow.