Of the city's population over the age of 25, 53.8% (vs. a national average of 27.4%) hold a bachelor's degree or higher, and 91.9% (vs. 84.5% nationally) have a high school diploma or equivalent. A 2008 United States Census Bureau survey showed that Seattle had the highest percentage of college and university graduates of any major U.S. city. The city was listed as the <answer>most literate</answer> of the country's 69 largest cities in 2005 and 2006, the second <answer>most literate</answer> in 2007 and the <answer>most literate</answer> in 2008 in studies conducted by Central Connecticut State University.
How was Seattle ranked on literacy in 2005-2006?
most literate