NEW YORK — America's weight problem isn't getting any better, according to new government research.Overall, obesity figures stayed about the same: About 40 percent of adults are obese and 18.5 percent of children. Those numbers are a slight increase from the last report but the difference is so small that it could have occurred by chance.Worrisome to experts is the rate for children and teenagers, which had hovered around 17 percent for a decade. The 2-to-5 age group had the biggest rise.The years ahead will show if that's a statistical blip or marks the start of a real trend, said the report's lead author, Dr. Craig Hales of the U.S. Centers for Disease Control and Prevention.The bad news is that the numbers didn't go down, experts say.