Histogram - where's the mistake?

Hi guys,

I am trying to plot a histogram but I seem to get the coordinates entries wrong. I have specified classes as you can see in the linked data (20,30,45,70), all the other frequency data should be correct too. Only when it comes to getting the coordinates right there must be a mistake in how I arranged the data (otherwise the histogram would not look the way it does when you plot one out of the x-y-chart.

This is the data (which I cannot upload as a .odf file because of low karma…):


Any help would be greatly appreciated!