The limited data available show that the amount of volunteer work is sizable and makes a significant contribution. For instance:

    Approximately 140 million people in the 37 countries studied engage in volunteer work in a typical year—that represents 12 percent of the total adult population of those countries.
    If those 140 million volunteers comprised the population of a country, it would be the 8th largest country in the world.
    Those 140 million volunteers represent the equivalent of 20.8 million full-time equivalent jobs.
    Volunteers make a US$400 billion contribution to the global economy; that would make it the 7th largest economy in Europe.
    Volunteer input represents 68 percent of total private philanthropy in the countries studied.
    Volunteers represent 44 percent of the nonprofit workforce in those countries.

These data were obtained through the Johns Hopkins Comparative Nonprofit Sector (CNP) and UN Handbook on Nonprofit Institutions in the System of National Accounts projects, conducted by the Johns Hopkins Center for Civil Society Studies in conjunction with Local Associates and national statistical agencies, respectively. You can explore additional findings from both projects here.

National volunteering data produced by governments. A few governments around the world conduct regular research on the voluntary sector, however, this data is not comparable between countries, and often over time, because each of these surveys utilizes a different methodology, sampling size, and definition of volunteering. The data provided in the links below does, however, afford us valuable snapshots of some portion of the volunteer work happening in each country at a particular time.

Canada Survey of Giving, Volunteering and Participating

Volunteering in America 2010 – National, Regional, State, and City Information

Swiss Federal Statistical Office Overview of Voluntary Work

Statistics Norway Satellite account for non-profit institutions, 2006-2008: Increased value added in non-profit institutions

Australian Social Trends, 2008: Voluntary Work

New Zealand Office for the Community and Voluntary Sector: Volunteering research and resources