Decade

Amount of Cities

Population

Coverage

Density

1940

412

128051

19.2

6742

1950

481

128811

19.5

6536

1960

673

112400

22.8

5340

1970

835

104785

28.5

4673

1980

944

97756

32.8

3998

1990

1063

98108

34.9

3783