WASHINGTON (AP) _ About $8 billion more a year is needed for education in the world's poorest countries to fulfill a pledge that every child on earth have a basic level of literacy by 2015, a new study says.

That pledge by 155 nations was originally made in 1990 and had the millennium's end as the goal. The date later was pushed back.

According to the report released today by the global relief agency Oxfam, some 275 million children worldwide are not in class or will leave school unable to read or write.

Across the globe, the report found 125 million children _ two-thirds of them girls _ never have been in a classroom. An additional 150 million had started school but dropped out without minimal literacy.

If current trends continue, sub-Saharan Africa, which now accounts for one-third of out-of-school children, will have three-fourths of the total in 15 years, according to Oxfam.

Oxfam, which includes 11 nongovernmental organizations around the world, lobbies governments and world financial institutions to fight poverty and raises money for anti-poverty efforts in more than 100 countries.

The group is beginning a campaign to get wealthy nations and private donors to increase aid and grant debt relief to nations with high illiteracy rates.

The report cites one of the world's poorest countries, Uganda, as an example of what can be done to improve education.

With outside help and new government policies, Uganda spends 17 times as much on primary education as it did in 1990. Enrollment has doubled over the past two years and now is estimated at close to 90 percent.

A key factor in the improvement was the abolition of high fees parents had to pay so their children could attend school.

Nonetheless, the number of children from poor countries who never have been to school equals the entire population of youngsters ages 6 to 14 in North America and Europe, the report says.