Annualizing 6 mos. of data

I need help annualizing 6 months worth of data. The data for the first 6 mos. is as follows:

1/31/2011: 0.9%
2/28/2011: 0.0%
3/31/2011: 0.9%
4/30/2011: 2.8%
5/31/2011: 0.9%
6/30/2011: 4.7%

I've seen formulas for annualizing 12 mo. data streams, but am unsure how to translate that for 6 mos. of data.

Thanks for your help!

Hi and welcome to the board

You have posted in the Outlook forum. is this correct?