How to show overlapping value in a bar chart? Probably in a Gantt or similar.

I would like to have a bar graph of the following data showing overlapping instances like a gantt chart. Can someone tell me if this is possible?

X-axis: 1 to 15
Y-axis: 1 to 15
*(both axis increment by 1 regardless of values below)

Value-Start - Value-End
4 - 6
4 - 5
6 - 9
6 - 7
6 - 9
10 - 11
12 - 13

I would like to show a graph like attached picture which shows the overlap of 1st and 2nd row and 3rd, 4th, 5th row.
***The most important thing here for me is the Y-axis because it shows me the highest overlap which is the three between 6 to 9. ***
You can ignore the color-coding that I made there but if that can be it's also great - if not it's ok.

Once again, the most important function of this chart for me is the height of the Y-axis which shows to me at one glance that I had 3 bars stuck on top of each other between 6-9.

Is this possible to do using Excel? Please guide.

Thanks,

Originally Posted by Andy Pope

No picture attached

Thanks - now attached:
bar-chart.png