How to understand the social security statement?

As of October 2008 my statement claims I have 36 credits. The statement claims that the 36 credits are assumed for last year and this year if I continue to work. What do they mean by that? By this year do they mean by my birththday (since I receive the statement three months prior) or do they mean another 12 months from the statement date?|||They mean Jan to Dec 2008. SS assumes you will have the same job throughout the year 2008