I get the same answer always from the Bureau of Economic Analysis of the US Department of Commerce: "Volunteer hours are not calculable." Here is a link to their excuse. Basically, because it resembles women's work.
Poppycock! has been my standard reply. It is the replacement value of paying someone to do the work!
Likewise, childrearing, homemaking and housekeeping done in the family aren't included in the Gross Domestic Product of the USA.
Points of Light Foundation and Independent Sector calculate the average value of volunteerism each year. It's an average, including work in young professionals helping out in soup kitchens, medical specialists who do surgery in war zones, grandparents who do family day care so parents can work, etc. According to the latter:
Just a reminder: Your Holy Beggar works for a living, as meek as it might be. She also volunteers her expertise, time and other valuable resources.
You are welcome.
And remember ...
No matter what,
DON'T FORGET TO ASK FOR THE MONEY.