How do I automate the YTD average of the previous years (i.e. 2008, 2009, 2010, 2011) to update as soon as I populate the data for the current year (i.e. 2012)? For example, as of June 22, 2012 we have 121 total trading days. How do I automate the average of 121 days in 2008, 2009, 2010 and 2011?
https://www.box.com/s/7d358910e12355004224
https://www.box.com/s/7d358910e12355004224