Should Histogram with data over several orders of magnitude Normailse ?

I'm trying to generate a normalised histogram of event times ranging from 0.05 to 17.5 second with some 144 points, using the analysis menu as shown in the image.  The resulting histogram has values >1.

I must be doing something silly ... but what?

 

 

Histogram Menu "Normalised" histogram

As the dialog says, it's normalized to probability density, i.e. the area under the curve (assuming rectangular bins) is one.