TTAB New Filings and Performance Measures for FY 2011

The TTAB has issued its "New Filings and Performance Measures" for Fiscal Year 2011 (here). I note two things in particular. First, with more than 2,500 appeals filed in each of the last two years, why are there only about 450 decisions issued each year (including inter partes decisions). What happens to all these appeals? Are most notices of appeal filed and then not pursued, perhaps due to reconsideration by the Examining Attorney? Second, I note that the duration of pendency rose during the year. Is this a result of the push to finish the revision of the TBMP?