SECTION 1.  Section 20 of chapter 40B of the General Laws, as appearing in the 2006 Official Edition, is hereby amended by striking out the second paragraph and inserting in place thereof the following paragraph:—“Low or moderate income housing,” (i) any housing subsidized by the federal or state government under any program to assist the construction of low or moderate income housing as defined in the applicable federal or state statute, whether built or operated by any public agency or any non-profit or limited dividend organization, (ii) any mobile or modular homes, freestanding trailer units, and units in trailer parks, (iii) any group homes in current operation, the primary purpose of which is to house persons receiving services directly or indirectly from the department of mental health, the department of mental retardation, the department of social services, or any other human services-related department or subdivision of the commonwealth or of the United States, and (iv) the total number of section 8 vouchers, so called, issued by the housing authority of that specific city or town.