Moderate and low-income Americans are far more generous with their time and money than are upper-income citizens, a study by the Gallup organization said this week.

Also, the survey found that overall, seven of 10 Americans donated to charitable causes, giving an average of $790 a year and almost half - 45 percent - volunteered an average of 4.7 hours a week in time to charitable causes.The study, "Giving and Volunteering in the United States," was commissioned by Independent Sector, a non-profit coalition of 650 corporate, foundation and voluntary organizations and was described as the fullest assessment yet on the patterns, mo-tivations and satisfactions of giving and volunteering.

"Contrary to popular opinion, the well-to-do in America cannot be described as generous," said Brian O'Connell, president of Independent Sector.

"A minority of those who are comfortable financially are good givers and some of the country's wealthiest give dramatically large sums, but as a rule, people of means cannot be described as particularly caring," he added. "For that primary category of humaneness, it is the poor and struggling who generally lead the way."

The study found, for example, that contributing households with incomes below $10,000 gave an average of 2.8 percent of their income to charitable organizations or causes while those with incomes between $50,000 and $75,000 gave 1.5 percent; those earning between $75,000 and $100,000 gave 1.7 percent. Individuals with incomes over $100,000 gave only 2.1 percent.