We have detected at least 6 different date ranges where observational bias may have affected the data due to policy and/or technology changes.

They are as follows:

1851 - 1870
1871 - 1897
1898 - 1966
1967 - 1981
1982 - 1994
1995 - 2017 (current date)

There's nearly a month left in the 2017 Hurricane Season.

We'll be posting an update on the observationally modified power values shortly.