First of all, you can simply do a bar chart using the results and the
frequency that approximately looks like bell shaped. But obviously it
is not perfectly bell shaped because it is not perfectly normal
distribution. But what you see is the actual shape of your data.

However, if you would like to draw an envelope on the top of the bars
that looks like a perfectly normal distribution then what you should
do is to use the equation of the normal distribution and use the mean
(16) and standard deviation (2.582) from your data to generate the
values for each of the results values. If you plotted this new series
on the same graph as a line and turned on the option of smoothed line
then you will see a perfectly normal distribution on the top of your
real data.

Let me know if you need me to email the file to you.

Regards,
- AG