According to the US Postal Service's Household Diary Study for FY 2008, ad mail has declined 5.24% since 2006. Ad mail volumes for 2008 were at 99.4 billion pieces compared with 104.9 billion in 2006. This is a greater percentage decrease than correspondence mail, which dipped only half a percentage in the same time frame. Transactional mail dropped 2.34% during that period. In 2008, 41.7 billion transaction pieces were mailed.