Americans' life ratings were better in April than in any month since August of last year, according to a recurring index measured by Gallup-Healthways. The U.S. Life Evaluation Index score of 50.0 in April is up from 48.4 in March, but is still below the five-year monthly high of 51.1 from January 2011.

The Gallup-Healthways ratings classify Americans as "thriving," "struggling," or "suffering" according to how they rate their current and future lives on a ladder scale with steps numbered from 0 to 10 Americans' life ratings have steadily improved each month since November, when they sank to their lowest level in more than a year (47.2).

The percentage of Americans who rated their lives well enough to be classified as thriving increased to 53.5 percent in April, up from 51.7 percent in March, and is the highest this measure has been since last August. The current percentage of Americans who are "thriving" is slightly below the five-year high of 54.3 percent from February 2011.

The percentage of Americans who were struggling declined in April to 43.0 percent from 45.0 percent in March. The percentage suffering remained essentially unchanged at 3.5 percent, compared with 3.3 percent in March.

The state of Iowa has used a separate measure by Gallup-Healthways, the Gallup-Healthways Well-being Index, to measure its progress in the Healthiest State Initiative that began nearly two years ago.