12 weeks.
15 weeks and 6 days.
In January 2012 there were 4 weeks and 3 days.
A little over 13 weeks between Jan 1 and April 5 2009.
24 weeks and 5 days.
21 weeks (rounded down).
25 weeks and 6 days.
34 weeks and 6 days,
43 weeks and 3 days.
30 weeks and 4 days.
26.
32 weeks and 2 days.
25 weeks and 6 days in a normal year and 26 weeks in a leap year.