I have recently discovered a new utility program for those working with gedcom files. It is called Family Tree Analyzer and allows a gedcom family history data file to be loaded and analysed. It has a large range of reporting facilities one of which is to extract and report on the occupations of individuals.
The attached chart shows the top 10 occupations of those within my database.
You can see the most popular occupation by far was that of coalminer which is not surprising as the majority of the individuals from the records lived in North Somerset, in the area of the Somerset Coalfield.
The Family Tree Analyzer program is available to download from http://ftanalyzer.codeplex.com/