budget /revenue as the % for investment

[Anonymous]

hi folks,

i have data like this

id	start date	Enddate	Budget
1	11/27/2011	11/16/2014	1000
2	11/27/2011	11/16/2014	2000
3	11/27/2011	11/16/2014	3000
4	11/27/2011	11/24/2013	4000

And i have revenue for one month

jan 2012 revenue =2000

% for investment=total budget/revenue (jan12)

how can i achieve % investment for jan 2012.

thanks in advance.