The Species 2000 and ITIS Catalogue of Life Annual Checklist has been released each year since 2000 (excluding 2001).  Previous checklists can be queried below:

• Annual Checklist 2011 - 1,347,224 species
• Annual Checklist 2010 - 1,257,735 species
• Annual Checklist 2009 - 1,160,711 species
• Annual Checklist 2008 - 1,105,589 species
• Annual Checklist 2007 - 1,008,965 species
  
• Annual Checklist 2006 - 884,000 species
• Annual Checklist 2005 - 527,000 species
• Annual Checklist 2004 - 323,000 species
  
• Annual Checklist 2003 - 304,000 species
  
• Annual Checklist 2002 - 260,000 species
  
• Annual Checklist 2000 - 220,000 species
  

Alternatively you may prefer to download CD image files (ISO images) of the relevant checklist.