Visa Bulletin, Rate of Progression question

[enoc]

I noticed in 2008, the Priority date has moved 6 months, while in 2009, it moved 19 months, is there a reason why? Has the department of state increased the number of visas available or did they come up with a way to process things quicker?

NOTE: I'm speaking of the 4th class (brother or sister of a USC)

[enoc]

I noticed in 2008, the Priority date has moved 6 months, while in 2009, it moved 19 months, is there a reason why? Has the department of state increased the number of visas available or did they come up with a way to process things quicker?

NOTE: I'm speaking of the 4th class (brother or sister of a USC)