I think Joe has the right idea. Take me for example. My entire life, I've worked in various office occupations, be it medical, legal, government, financial, etc. Now I'm a self-employed bookkeeper. That's the one I would put as a category for myself, and then describe any interesting information about my other 'jobs' in my bio. Then, take my husband's career: He's been a heavy equipment operator most of his adult life. So only one category would really fit for him.