Sep,1931

30.7

March,1938

23.67

April, 1932

23.43

Oct, 1987

23.22

May, 1940

21.7

October, 1929

20.36

May, 1932

20.26

June, 1930

17.72

December, 1931

17.01

February, 1933

15.62

August, 1998

15.13