Utahns paid 7.4 percent more in federal and state income taxes during 1986 than they did the previous year, with payments totaling nearly $2 billion.

And preliminary reports indicate that state income taxes jumped 28 percent, or $128 million, in 1987 alone.The figures come from an examination of federal tax returns prepared by the Utah State Tax Commission, and were reported Monday by the Utah Foundation. The statistics also show that state income tax collections have jumped 650 percent since 1970 from a total of $62 million then to $465 million in 1986. Federal taxes increased 390 percent during the same period from $307 million $1.5 billion.

According to the study, both types of taxes continued to climb rapidly during 1987 and 1988 because of the Federal Tax Reform Act of 1986 and revisions made by the 1987 Utah Legislature.

Of the Utah returns filed in 1986, 93 percent reported a gross income of $50,000 or less, while 7 percent reported an adjusted gross income of more than $50,000. Because of graduated federal tax rates, the 7 percent paid more than 42 percent of all federal taxes paid by Utahns that year.

The highest average income per return $24,130 was reported in Davis County, while Piute County registered the lowest average per return at $12,233.