Israel's per-child investment in education is lower than the average among OECD countries at every stage of the educational process, according to the annual report on education published by the Organization for Economic Cooperation and Development Tuesday.

Moreover, while per-child investment in education rose by 39 percent, in real terms, in OECD countries between 1995 and 2006, those same years saw an increase of only 9 percent in Israel.

Israel also has the third most crowded classrooms in the developed world, after Korea and Japan, the report said, while its teachers' salaries are far lower than the OECD average.

Education Minister Gideon Sa'ar said the data "necessitates a national strategy of investment in education. We are in competition with the developed nations, which invest far more than we do in education."

The data in the report, titled "Education at a Glance," are for the years 2006-7 - meaning before Israel implemented its "New Horizon" education reform, which significantly raised teachers' salaries. But former education minister Yuli Tamir, who initiated that reform, said Israel must continue raising teachers' salaries in ord er to close the gap with OECD countries.

The report said the average per-child investment in education in Israel, as measured by purchasing power parity (PPP), is $3,803 for kindergartens, $4,923 for elementary schools and $5,858 for secondary schools. This compares to OECD averages of $5,260, $6,437 and $8,006, respectively.

Measured as a percentage of gross domestic product, which is considered a better measure of real investment in education, however, it turns out that Israel's per-child investment is similar to the OECD average for both elementary and secondary schools. Only for kindergartens is Israel significantly below the OECD average.

According to Prof. Ruth Klinov of Hebrew University, who analyzed the findings, Israel's per-child outlay on education, at every level, was similar to the OECD average back in 2000. However since then, investment in education has soared among the countries in the OECD, while Israel's investment has remained unchanged.

Teachers' salaries continue to be among the lowest in the developed world - though Israeli teachers also work fewer hours than do their OECD colleagues. Despite this, Israeli children actually spend more hours in school, at every stage of their education, than do their OECD counterparts. Children aged 7-8, for instance, spend 88 more hours in school each year than the OECD average, while for students age 15-17, the excess totals 183 hours a year.

Some of this gap is due to the fact that Israeli children study a relatively large number of subjects. However, this also results in Israelis spending a smaller percentage of their time on core subjects than the OECD norm.

As for class size, Israel averages 27.6 students per class in elementary school and 32.7 in middle school, whereas the OECD averages are 21.4 and 23.9, respectively.

On the positive side, 44 percent of Israelis aged 25-64 had college degrees in 2007, compared to only 28 percent in the OECD. However, this gap is closing rapidly: It was highest among people aged 55-64, and far smaller among people aged 25-34.