This document from the US Census shows the trend of shipments in the United States. Sales are down consistently, year over year, except for the small bump that took place
after Katrina in 2005.
A few observations:
Sales this year are off the pace of 2006.
The most sales are in Florida and Texas.
There are hardly any sales in the Northeast. More sales occur in North Carolina in one year than in New Hampshire in six years, for example.
Some years, there are sales of manufactured homes in the District of Columbia. I am not sure that I have ever seen a manufactured home in the District. Maybe near the C & O Canal?