Going abroad, the first thing we do is to compare the price of consummer goods there. While shopping and eating at restaurants we realize how expensive or cheap things are. I instinctly figure out the living standard of countries from their price of goods. But there is no quantitative way of measuring living standard. I have regarded GDP per capita as a handy way to estimate the living standard. This figure is said to vary with current exchange rate and so it does not represent the living standard correctly. But Japan's rank in the list of GDP per capita went up from 2013 to 2015 despite the depreciation of yen during this period. So it roughly represents the living standard. IMF's survey on GDP per capita in 2015 shows that Japan ranks 26th, after Singapole (11th) and Hong Kong (16th). And it is said that Korea (30th) will overtake Japan soon.
Recently someone told me that human development index represents the living standard more appropriately. It consists of life expectancy at birth, years of schooling and GDP per capita. For this index Japan ranks 20th, after Singapole(11th), Hong Kong(12th) and Korea(17th). However in 2011 Japan ranked 12th above Hong Kong and Korea. As seen above, Japan is going down also in the list of this index. I guess GDP per capita is the most important factor of the three to estimate this index.
What caused Japan's GDP to fall ? I figure out that the growth in the number of low income nonregular workers is the main reason. Other cause is relatively small number of women who work. If more women and senior people join work force, GDP per capita will surely go up.