Year

Dissimilarity Index

1860

0.98

1870

0.97

1880

0.93

1890

0.85

1900

0.75

1910

0.76

1920

0.74

1930

0.72

1940

0.71

1950

0.58

1960

0.66

1970

0.54

1980

0.41

1990

0.35

2000

0.29

2010

0.26

2018

0.24