I have a database like this:
Year Type Return
1900 A 4
1900 B 7
1901 A 87
1901 B 3
1902 A 9.7
1902 B 2
I would like to transform the return absolute values into yearly percentages.
Eg. For 1900 I would like to have:
4/(4+7) = 0,36
7/(4+7) = 0,64
And:
Year Type Return
1900 A 36%
1900 B 64%
The real database has >10k lines of rows.