Aperture & libraries
You can export folder (in your example 2009) as a library. This self contained library can be stored where you like and once reattached it is very easy to switch libraries from within Aperture. The only shortcoming of this is that images from 2009 are only available when that library is open.
|Keyboard Corner by SilvanBromide|
from Show Us KEYBOARDS!
|Moss Point Blue by Gary Zuercher|
from The blues.
|Ljubljana by SSonic|
from Streets #6: Streets in Monochrome
|Music written in landscape by Schjeldal|
from Abstract Photo - Landscape