How to sum one number each 24 lines

Hi!
I have hourly data through an entire year in columns, so in every line i have a different hour of a day. but i want to make another column to introduce the number of the day of the year that where we stand.
It is a bit difficult to explain, so i'll try to give an example-> For 4th March, i have:
Hour Data Number of the day
1 67 63
2 500 63
3 444 63
4 567 63
... ... ...
(the last column is what i want - 4th March = 31+28+4=63th day of the year)
So, what i want is some form of summing one day each 24 lines, so that in the Hour '1' on the 5th of March i would have 64 in the last column.

Thank you!