U.S. stocks were trading at 22.7 times the total earnings of the companies in the index in March 2013, averaged over the past 10 years and adjusted for inflation, according to data developed by Yale University economist Robert Shiller. This is closer to the average of 19.5 times adjusted earnings seen in the last 50 years. In 2000 the level reached 44 times adjusted earnings. Using operating earnings according to data developed by Howard Silverblatt of S&P Dow Jones Indices, the S&P 500 is 15.9 times operating earnings in March 2013. This compares to 28.4 times in 2000 and a long term average of 18.8 times. The European markets are about 25% cheaper says Zweig, with European shares for Ireland, Italy, France and the UK trading at less than 15 times the average of their long term adusted earnings after inflation. By comparison Japan is at 19 times long term adjusted earnings.