LYNN-Legislation co-sponsored by Rep. Steven M. Walsh, a Lynn Democrat, and passed by the House, increases funding for the Massachusetts Rental Voucher Program, which helps low-income households pay their rent in private apartments by subsidizing a portion of the amount.The vouchers pay the difference between 40 percent of the tenant’s income and the rent.”The high cost of housing has become the number one concern for most of my constituents,” said Walsh. “Working families are finding it increasingly difficult to pay the rent or mortgage, resulting in homelessness or foreclosures.”Walsh said funding the voucher program alleviates that pressure and stabilizes those families most at risk.According to the Boston-based Citizens’ Housing and Planning Association (CHAPA), Massachusetts is still among the least affordable states in the country based on housing costs.Housing currently enrolled in the voucher program have an average household income of $958 a month. The fair market rent for a two-bedroom apartment in Greater Boston is $1,366.Consequently, the state’s family shelter program is operating beyond capacity. Approximately 1,950 families live in state-funded shelters. The state pays an average of $3,000 per month to house these families, while the average family on a voucher costs taxpayers $532 a month.Aaron Gornstein, executive director of CHAPA, said increasing the voucher funding is a cost-effective way to prevent homelessness.