Here's some recent analysis from Dimson,Marsh and Staunton (based on +100 years of global equity returns).

http://ssrn.com/abstract=891620
"Over the long run, real returns accrued largely from dividend payments, but Dimson, Marsh and Staunton (2000, 2002), Arnott and Ryan (2001), and Ritter (2005) highlight the time-series and cross-sectional variation of global equity premiums."

http://www.investmenteurope.net/digital_assets/6305/2013_yearbook_final…
"We show that, historically, for the world equity index, the annualized mean dividend yield has been 4.1%, while real dividends grew by 0.5% per year and the annualized expansion in the price/dividend multiple was 0.4%."