The number of seats in the Japanese local municipal assemblies ― excluding special wards in Tokyo and municipalities which had experienced the merger before FY 2002 ― fell from 57,179 to 33,022 by 42.2% between FY 2002 and FY 2009 as the result of reduction in the number of municipalities due to the mergers. The number of seats declined by 16.7% in the merger non-experienced municipalities, while it did by 58.8% in the merger experienced municipalities. 123 of 580 merger experienced municipalities have the number of seats equivalent to the maximum or more of prescribed number of seats by their scale. But the extra number of seats gradually lessened as the years passed after the merger. The number of population per assembly member increased from 2,064 to 3,572 by 73.0% in total; 21.6% in the merger non-experienced municipalities, 130% or more in the merger experienced municipalities. Nevertheless the number of seats in the merger experienced municipalities is above that of similar scale municipalities which have no experience of merger.
It seems that many merger experienced municipalities determined the compensation of assembly members at the maximum level among the former municipalities. But the compensation rose 1.2 or more fold in 97 out of 282 merger experienced cities with a population of less than 100,000. The compensation and allowances of the municipal assembly members declined from 241 billion yen to 142 billion yen by 41.0% in total; down by 14.6% in the merger non-experienced municipalities; down by 56.5% in the merger experienced municipalities. While the compensation and allowances per assembly member remained almost flat, the compensation and allowances per population fell by 29.0% in total, by 18.6% in the merger non-experienced municipalities, by 51.0% in the merger experienced municipalities.