Small-business optimism nationally is the highest it has been in five years, according to the latest Wells Fargo/Gallup Small Business IndexThe quarterly poll was conducted through telephone interviews with 602 small-business owners July 22-26. The key driver of the 9-point jump from the second-quarter index is business owner optimism around availability of credit now and in the future. Improvements in the housing market also are benefiting about 47 percent of business owners.