It should not surprise anyone that we've seen a significant increase in e-prescribing at the national and state level between December 2008 and June 2012. According to the ONC, 48% of physicians are e-prescribing using an EHR on the Surescripts network.
States that had the highest growth in percent of physicians e-prescribing using an EHR include New Hampshire, North Dakota, Wisconsin, Iowa, and Minnesota from December 2008-June 2012.
Massachusetts (77%), New Hampshire (74%), and Iowa (73%) had the highest rate of physicians e-prescribing through an EHR.
View the ONC report "State Variation in E-Prescribing Trends in the United States" here (PDF)