Email open rates fell to 17% on average in 2010, down 9 percentage points from 26% in 2009, according to a report by Harte-Hanks.The pharmaceutical and government sectors recorded the highest open rates during the year, whereas the tech sector recorded the lowest. 

Below, other findings from the Harte-Hanks Postfuture Index 2009-2010, which examined metrics for roughly 3 billion email messages sent by 100 companies in nine vertical industries. 

The declines in open rates are likely due to changing patterns in the use of text and imagery that records open activity, according to the report. Meanwhile, email click-through rates stayed flat (at 3%) over the period.

Delivery rates were up slightly, reaching 95% on average in 2010, up 2 percentage points from 93% a year earlier, while unsubscribe rates fell to an average of 0.16%, one-half the 2009 average of 0.32%. 

A few key industries outperformed others in click- and open-rate performance during the year:

• The highest click rates were recorded in the insurance sector (8%), well above the average click rate of 3%, while the lowest click rates recorded were in the tech sector (less than 1%).
• The pharmaceutical and government sectors recorded the highest open rates in 2010, 26% and 25%, respectively, whereas the tech sector recorded the lowest open rates (6%). 

Email content in the pharmaceutical sector tends to be highly targeted to individual subscribers, Harte Hanks points out, driving higher open rates, whereas tech companies tend to acquire large numbers of subscribers via events (e.g., trade shows), audiences that may not have a specific interest in receiving email communications.

Looking for solid, substantiated information about email from the industry's best resources? The 67-page Email Marketing Factbook featuring 39 charts tells you about email usage, what captures users' attention, and how organizations are using email to reach customers. This email factbook consists of chapters 1 & 2 from the larger Digital Marketing Factbook a 144-page compilation of data and 110 charts that also covers search engine marketing and social media.

Other key findings:

• The retail sector continued to enjoy high delivery rates—over 98% in 2010 (vs. 97% in 2009), whereas the auto sector recorded the lowest delivery rates at 90% in 2010 (vs. 88% in 2009).
• Bounce rates averaged 5% for 2010. Automotive (12%) skewed this rate high. Without that sector, the average bounce rate for 2010 was 4%, a strong improvement over the 2009 bounce rate average of nearly 7%.

About the data: The Harte-Hanks Postfuture Index 2009-2010 examined metrics for roughly 3 billion email messages sent in 2010 by about 100 companies in nine vertical industries using the company's Postfuture email platform.