Editor/Writer/Researcher for Demographic Website

I run a demographic website and am looking for some regular help. I'd like someone who can contribute a certain of hours monthly. The work includes: proofreading existing articles, adding sources/citations for current articles, extending articles with new content, and coming up with new article ideas.
The content is primarily related to the population of different areas, including history, projections, racial breakdown, etc...

Please include any relevant samples of your work, and any previous similar positions. Also include how many hours you are available per month.