Homeowners in a single congressional district in California, the 14th District in Silicon Valley, took more in mortgage interest write-offs than all the residents of six whole states combined, claiming $3.2 billion in mortgage interest deductions during the year covered by the study. By comparison, $2.9 billion in write-offs were recorded by residents of Vermont, Wyoming, Alabama, North Dakota, South Dakota and West Virginia. The average write-off in that particular California district was $35,000, compared with an $9,500 average nationally.