CONCORD, N.H. — As Congress considers legislation to overhaul the tax code, a public policy group is looking at how the existing code affects New Hampshire residents.

The New Hampshire Center for Public Policy Studies analyzed IRS data from 2015 income tax filings in New Hampshire. Altogether, that amounted to 693,000 tax returns filed accounting for $7 billion paid in federal income taxes.

Researchers say the data affirm wide disparities in the distribution of income and its sources. The wealthiest 1 percent as measured by adjusted gross income reported incomes 115 times that of the bottom 31 percent. That bottom 31 percent paid 1 percent of the total federal income taxes paid by New Hampshire residents, while the top 1 percent paid 28 percent of the total.