There are roughly 102.5 million eligible voters in Japan, the home affairs ministry said Tuesday as official campaigning for the Nov. 9 general election began.

The exact total is 102,536,507, up 1,825,552 from the previous House of Representatives election in 2000, according to the latest voter registration data released by the Public Management, Home Affairs, Posts and Telecommunications Ministry.

A person must be at least 20 years old to be eligible to vote.

Of the single-seat constituencies that will elect 300 Lower House members, the Tokyo No. 6 district has the largest number of voters at 461,774. The smallest number was 214,327 in the Tokushima No. 1 district on Shikoku Island.

The number of voters per lawmaker in the most populous district is 2.15 times that in the least populous district.

This disparity in the weight of votes between such districts is down from 2.47 times in the previous election.

This is due to a reapportionment of seats after a 2002 revision of the Public Offices Election Law that eliminated a single-seat constituency in five different prefectures but also increased the number of such districts by one in five other prefectures.

Three prefectures -- Akita, Wakayama and Yamaguchi -- saw the number of registered voters decline, while Tokyo witnessed the largest increase, followed by Kanagawa and Saitama prefectures.