In looking at this it looks like the major difference btwn. '04 and '05 comes in comparing the month of October. Must be attributed to the hurricane season of '05.
YTD numbers are definitely down across the board between '04 and '05 though, but shocked to see that lot sales YTD are only down @ 1%. Again, I think the dramatic difference between October '04 and October '05 skews the YTD numbers quite a bit.
All in all after a phenomenal '04, on paper the '05 volume decrease does not look that depressing. At least the '05 prices are well ahead of '04.
Let's hope '06 is back on the rise.