Some recent stats on email delivery rates:

The highest delivery rates in DoubleClick’s report are in retail, at 93.8 percent, consumer publishing, at 93.3 percent, and business publishing, at 93.1 percent success rates. The lowest delivery rates were found in financial services at 88 percent, business products and services at 88.4 percent, and consumer products and services, both just over 90 percent.

Read more: E-mail Delivery Rates Up, Click Rates Mixed