Small businesses aren't thriving, but they are feeling about as optimistic as they were heading into the recession. The National Federation of Independent Business' Optimism Index (.pdf) rose again in February to 94.5 from 94.1 in January. That's not a huge gain, but it virtually matches December 2007's value of 94.6. In good times, however, it's normal for the index to be at or above 100. Although the index didn't move up much in February, some key components improved. First, here's a chart of ...