The National Association of Home Builders said today that its monthly measure of the mood of its membership showed a modest improvement this month, just enough to boost its housing market index 1 point to 61, the highest level since November 2005. The index measuring buyer traffic rose to 45 in August from 43 in July, while the component gauging current sales conditions ticked up to 66 from 65. The index charting sales expectations in the next six months held at 70 in August, unchanged from the previous month.