[AccessD] 53 Work weeks in 2007?

Last year I was using the following to get the week number:

WorkWeek = Val(Format("1/2/06", "ww", vbMonday)) - 1 )

The work week for my customer started on a Monday 

I never really understood why I had to add the "minus one", but the first
Monday and remaining week of 2006 would return a "2", so I just subtracted 1
and all was fine.

But this year, there are 53 Mondays so this line of code returns a "0" for
the first week of January.

Is there another way I should be getting the work week number?

John