Religious institutions received nearly half of every charity dollar Americans contributed last year -- more than three times the amount received by educational institutions or hospitals.

According to the current report of the American Association of Fund-Raising Counsel, Americans gave an estimated $18.4 billion to churches and synagogues in 1978, or 46.5 percent of total charitable contributions.

The figure for religious institution gifts does not include donations to church-related schools, hospitals or other institutions not primarily involved with worship, evangelism or missionary work an association spokesman said.

Educational institutions, including church schools and colleges, received 14 percent of the $39.56 billion total that Americans gave last year, while hospitals and health enterprises received 13.8 percent.

The statistics on Americans' generosity are included in a report just issued by the National Council of Churches.

In its own independent study of giving within Protestant churches, the NCC reported that in the 10 major denominations it monitors annually, per capita giving was 2 percent ahead of inflation in 1979.

At the same time, membership declines in these churches caused their total income to fall half a percentage point below the inflation rate.

This year 42 protestant denominations were included in the NCC's study. Their members gave an average of $176.37 to their church in 1978. While this is a substantial dollar increase over the $159.33 average of 1977, it represents only a 3 percent increase after inflation, the NCC said.

Theologically conservative Christians continue to give the greatest amounts per capita to their churches according to the NCC study.

Top givers for 1978 were the Independent Fundamental Churches of America, with $658.16 per capita; the Seventh-Day Adventists, with $617.39 per full member; and the Free Methodist Church of North America, $613.29.

Southern Baptists gave an average of $150.45 to their church, which is the nation's largest Protestant denomination.

The lowest per capita contributions, $50.13, came from the Arfican Methodist Episcopal Zion Church.