* The number of volunteers in the United States increased 23 percent from 1988 (80 million) to 1990 (98.4 million).* Volunteers put in 20.5 billion hours in the same period, with a dollar value of $170 billion. * The less affluent are still proportionately more generous than the wealthy. In 1989, contributing households with incomes under $10,000 gave 5.5 percent of their household income to charity. Those with incomes between $50,000 and $60,000 contributed 1.7 percent; those between $75,000 and $100,000 contributed 3.2 percent; and those with household incomes of $100,000 or more contributed 2.9 percent. * The average contribution for all households (including non-contributors) is $734 a year, about 2 percent of annual household income. That's up 20 percent from 1988 when it was $562 (an average of 1.5 percent of household income.) * Those who give and volunteer regularly to their church or religious institutions are the leaders in doing the same for all other causes. * Volunteers contribute more money than non-volunteers, and contributing households that also volunteer give a much higher percentage of their household income than households that do not volunteer. * A higher proportion of respondents reported volunteering from the Midwest (58 percent) and the West (57 percent) than from the South (51 percent) and East (50 percent). Source: Independent Sector/Gallup survey, 1990.