How to tell(simplistically) if the market is expensive?

Both Dow Jones and S&P500 has hit and continue to stay at new high, questions have been asking if one is still able to invest in this market.
One of the quick way would be to look at the CAPE ration as a quick guide to determine which market one can invest. Cyclically-adjusted price-earnings(CAPE) ratio was introduced by Graham and Dodd, latter on also used by Robert Shiller. Cambria Quantitative Research's Mebane Faber extended the used of the ratio to measure global markets. Below is a chart which shows how the world markets ranks from cheapest to expensive.

Source:businessinsider.com

From the chart, it seems that most of the European countries are fairly cheap. In the middle, we have few from Asia. At the top end, to name a few, there is the US, Indonesia and Malaysia. Malaysia came as a surprise to me though ... ...