The phrase "percent improvement" refers to the positive change or progress in a certain aspect, usually measured in comparison to a previous value. It indicates how much better something has become, expressed as a percentage. Full definition
The vehicles in use already have shown a nearly 50 percent improvement in fuel economy. (fooddrink-magazine.com)
Fuel economy is rated at 33 mph highway for front - wheel drive models, which is an 18 percent improvement over last year. (autoweek.com)
After 24 weeks of treatment, children in the parent - training group showed a 48 percent improvement on parent ratings of disruptive behavior compared to a 32 percent decline for parent education. (sciencedaily.com)