JupiterResearch forecasts that email marketing spending will grow from $885 mln in 2005 to $1.1 bln by 2010, and the volume of spam messages per consumer will decrease by 13% a year during this same period. Filtering improvements made by Internet service providers are credited with the expected decline in spam. The average active email consumer will see a drop from 3,253 pieces of spam in 2005 to 1,640 pieces of spam in 2010. E-mail delivery rates have stabilized at an average of approximately 88% and are expected to surpass 90% over the next few years. By 2010, the cost of incorrectly blocked email will drop to $92 mln from a high of $107 mln in 2006.