Adding Data totals

[john.9.williams]

I have two columns of data column a is always the sane coloum b get
filled out every week with numerical data for instance

data1 10
data2 9
data3 6
data4 4

at the end of the week i want to add the totals in column b to another
sheet but every time add the current weeks data to that what has
already been done

i.e

running total

data