(1) The net average income in "constant 2005 US$" is computed using the Interbank nominal exchange rate [a] and the U.S. inflation rate [d]. The net average income in "constant 2005 US$" at PPP is computed using the OECD PPP exchange rates for actual individual consumption [l] and the U.S. inflation rate [d]. The latter reflects the purchasing power in the United States in 2005. (2) The gross monthly average income is based on data supplied by the Japan Ministry of Health, Labour, and Welfare [18] to the International Labour Organization [9] and to the Japan Statistical Yearbook [17]. The average income includes the salaries and wages of paid employees. Employees include both men and women unless otherwise noted. The average income by sector include the bonus and are limited to the regular (full-time) employees working for enterprises with 5 or more regular employees. The average bonus in 2005 is of 2.3 months salary for regular employees working in enterprises with 5 or more regular employees [17]. In the education sector and the gas-electricity sector, the bonus reaches 5 months salary. (3) The compulsory deductions are obtained from the OECD Tax Database [k]. The deductions include national income tax, municipal tax, prefectural tax, and social security. The deductions are representative of single-earner-married-without-child status. The deductions on the average salary are confirmed through the difference between the gross and net household income in Japan (16%) [6]. (4) The number of hours is based on data supplied by the Japan Ministy of Health, Labour, and Welfare, to the International Labour Organization. The hours correspond to the hours actually worked. The hours by sector reflect the average of employees in establishments with 10 or more regular employees.