Vlookup problem

Hi guys

its such a basic question, i don’t know why i am asking it, but for some reason my vlookup isn’t working

i have created a column called 2011net sales,
I have dumped sales figures on the work sheet called data

All i need is for a vlookup to look at column A sheet “summary” go the data sheet, if there a 2011 figure, return it as a value

For account 878505750884 net sales 2011 is 40624.38