It has recently been claimed that Japanese society has entered a stage of “few births and deaths, with an aging population” [1]. The total fertility rate (aggregate total birth rate of women by age in a given year) has been on the decline, and has continued to record alltime low numbers, falling from 2.13 in 1970 to 1.34 in 1999 [2]. The average life span

for Japanese males and females was 69.3 years and 74.7 years, respectively, in 1970. By 2000, however, it was 77.6 years and 84.6 years [2]. The population aged 65 or over in Japan was 7.4 million in 1995, accounting for 7.1 % of the total population, and it is 22.3 million in 2000, accounting for 17.5% of the total population [2]. With this aging of Japanese society, it is feared that social security benefit expenditures such as medical care and pensions will increase tremendously [1].