title: updating a line chart for each import of data
body: <p>i have created a master progress check workbook. it has an import button, when clicked runs a macro to copy data(progress percentage) from the field workbook to the master workbook. The macro also runs an "input box" asking the user for the date of the given data.
  This data is then used to calculate the overall progress report for that date.</p>
  
  <p>this is where im stuck.... now i need to create a line chart of "percentage progress" vs. "date".
  hence for every import i have to store the old values with its date of import and add this to the chart</p>
  
  <p>my vba skills are still weak, as i have just started... help would be much appreciated1</p>