Combine Xls files and produce statistics

We require a freelance to put together production reports for the past two years. These are in individual spread sheets. Then provide a graph per month for production under various categories such as total production, production by supervisor, production by shift, production by different types of equipment. This will require a strong understanding of Microsoft excel. There are 24 individual spreadsheets each with 31 lines and the maximum size of each file is 2 meg.