Long-term historical data on price/earning ratios, price/book ratios and dividend yields for stockmarket indices is extremely valuable in looking at long-term returns – but it can be very difficult to obtain. While price data is available for many major markets stretching back decades or more, valuation data typically hasn’t been recorded so carefully.
The figures that are available have usually been reconstructed from old earnings reports and are proprietary data sets that are expensive to access. For those who are willing to pay, Global Financial Data is probably the most comprehensive source for very long-term financial data of all kinds.
For those who can’t justify the cost of paid-for data, there are a few freely downloadable data series for some of the major indices around the world, although they are often hard to find and there is no consistency about which markets are available. The following links will take you to the ones I’ve found that are still updated – if you’re aware of any others, please let me know in the comments below or by email.