The International Labour Organization (ILO) is the best resource for historical statistics on labor force participation rates. Use their ILOSTAT database. Under Browse Indicators by Subject, expand the selection for Population and Labour Force and look for Labour force participation rate. Click on the link for By Sex and Age. This will open up a large table with many countries and years of data. Click on the Customize button to narrow by country (Reference Area --> Country A-Z) and year (Time & Frequency). You'll be able to download all available ILO data, from population censuses, ILO model estimates, and more.