Dates Formatting in Excel

Hi All,

Thanks in advance for your help. I am autoformatting my dates in Excel 2007 to read as mmm-dd-yyy (i.e. Jan-01-2010) which is working perfectly. However, I also want to have the option to put in partial dates such as (only) "2010". However, if I simply input 2010 into the cell, it calculates based on Excel number dates (it converts it to Jul-02-1905). Is there any way for it to autoformat to when the date is fully filled in but also allow you to input partial dates?