Your tax dollars at work and play; Spending by all levels of government in the United States will top the trillion-dollar mark this year, a tax research group figures. To be exact, the Tax Foundation Inc. says federal, state and local units of government will spend $1.07 trillion in fiscal year 1981, which ends Sept. 30. That is up from $942.4 billion in the last fiscal year. The 1981 spending works out to $4,678 for every American. In comparison, it was $1,643 in 1970, $846 in 1960 and $468 in 1950. The federal government will spend $710.4 billion of the 1981, estimated total, said the foundation, a non-profit research organization. "Since 1975, federal outlays have grown by 109 percent, while state-local expenditures have increased by 63 percent," the group said. Going back even further, the group estimated that total 1981 spending will be about 15 times greater than in 1950. "Federal expenditures will be almost 16 times as large, and state-local outlays 14 times as large as they were 31 years ago." All levels of government spent a little more than $70 billion in 1950, with the federal chunk at $44.8 billion, the group said. The group does not take inflation into account in its computations, but goverment figures show inflation accounted for only about a 250 percent rise from 1950 to the first quarter of 1981. In 1980, the foundation estimated that the federal government spent $618.2 billion and state and local units $324.2 billion, which works out to $4,171 for every American. The total bill in 1979 was $832.4 billion or $3,726 for every American. The federal share was $535.7 billion.