This index method groups together Kanji that share strokes between them (particular the left-hand side stokes), for example the Kanji 試 and 計 would be grouped together.
... the census of 2000, there are 19,701 people, 6,700 households, and 5,011 families residing in the town. The population density is 1,549.2/km² (4,010.1/mi²). ...