What was the percentage increase or decrease in fatal accidents per 100,000 aircraft hours between 1960 and 1970? calculate the percentage and place then choose increase or decrease. and what was the percentage increase or decrease in airline fatality rates between 1950 and 1975? calculate the percentage and then choose increase or decrease.

The first answer is 39.47% decrease.
The second answer is 96.19% decrease.

Explanation

For the first
The number of accidents per 100,000 aircraft miles in 1960 was 0.38.  In 1970 it was 0.23.
To find the percent increase or decrease, we first find the amount of increase or decrease:
0.38-0.23 = 0.15.
We now divide this by the first amount, 0.38:
0.15/0.38 = 0.3947 = 39.47%
Since it went from 0.38 to 0.23, this is a decrease.

For the second
The value in 1950 was 3.15 and the value in 1975 was 0.12.
We first find the amount of increase or decrease:
3.15-0.12 = 3.03
We now divide this by the first number, 3.15:
3.03/3.15 = 0.9619 = 96.19%
Since it went from 3.15 to 0.12, this is a decrease.