Jun

Feb

Mar

Apr

May

June

July

Aug

Sep

Oct

Nov

Dec

1973-1982

5.1

−2.8

−20.0

−4.1

−27.1

−50.6

−52.4

−51.1

−38.2

−35.1

−19.8

−5.7

1983-1992

−11.8

−8.9

−21.9

−31.4

−30.3

−48.3

−60.7

−58.8

−44.8

−25.8

−7.5

−2.6

1993-2002

−5.3

−8.2

−18.3

−27.3

−42.4

−51.4

−60.7

−58.1

−44.6

−11.5

−15.6

−15.5

2003-2016

−9.9

−7.7

−18.5

−28.4

−37.2

−50.5

−57.4

−57.5

−33.5

−21.6

−19.8

−7.3

N = Average(D)

−22.0

−27.7

−78.8

−92.1

−138.0

−200.9

−231.4

−225.6

−161.3

−94.1

−62.9

−31.2