Fig 1.
Map of Japan indicating study site regions.
Japan is indicated in black and gray: Black shows where the data for the analysis were gathered; the gray areas show where the data were excluded, that is, Hokkaido, Tokyo, and Okinawa. This map was created based on Natural Earth data (http://www.naturalearthdata.com/).
Table 1.
The descriptions of the variables used in Tobit models.
Table 2.
Estimation results of the Tobit models.