Creating a new list with aggregate of values of a column from another list

Question

I have a named list of 152 elements(daily values), each having 12 columns, I wish to create a new list with the sum/aggregate of the values of the column 11 year-wise...(the 12th column in my original contains the year-this is the daily dataset of sediment at 152 stations)

The result should be

list A

$Station 1

year 1971, 1972,1973.....

x 1276,13698,216895

$Station 2

year 1971, 1972,1973.....

x 1278,1898,21625