Aug 13. Confidence of US consumers in the national economy improved in August due to lower gasoline prices, but remained below 50 points, according to a poll by Investor's Business Daily and research company TechnoMetrica Market Intelligence. The Economic Optimism Index rose to 41.8 in August from 37.4 in July. A reading above 50 points suggests prevailing optimism and below 50 points to pessimism.