Auto updating graphs as new data becomes available

Hi Folks,

I have a excel sheet which will be updates with performances of yesterday. Was looking at presenting the data in a 7 day trending graphical format. So when yesterdays data is populated the graph has to be automatically updated by it removing the data of 7+1 days data and including yesterdays data. Please find attached a an excel for better understanding.
Please help... feel free to ask if any more info is required

Hi I want to calculate employee strength/ count (headCount) month wise, Request you to help me in this?