More detail is required.
What do you currently have in the column and what do want after the increase?
If you want to increase all data by the same amount by adding, place the
increase in an unused cell.
Copy that cell then select the data cells and Paste Special>Add>OK>Esc.
To change all by 10% just enter 1.1 in the unused cell then use the the Multiply
option from Paste Special.
Gord Dibben MS Excel MVP