Section 66A. Any domestic life company may purchase, lease or acquire by gift or otherwise and hold without any limitation of time any real property, or any interest therein, in any state of the United States in which it is authorized to transact business, in Puerto Rico if authorized to transact business therein and in the Dominion of Canada where authorized to transact business therein, and may use such property, as well as any other real property, owned, held or leased by it for a housing project designed to provide accommodations for twenty-five or more families. Such company may use existing structures, may erect or cause to be erected new structures, may use any combination of existing structures and new structures and may maintain, repair, alter, demolish and reconstruct such structures. The word ''structures'', as used in this section, shall include apartment or tenement buildings, and dwelling houses, and buildings or accommodations for retail stores, shops, offices and such other community services as the company may deem proper and suitable for the convenience of the tenants and occupants of such structures, but shall not include hotels. Such a company, alone or jointly with others, may collect and receive rents or income from and may manage, lease, mortgage, sell and convey the whole or any part of such property. No real property shall be purchased, leased, held or improved under this section if the cost or value thereof, or the estimated cost of proposed improvements thereon, or both of them, as the case may be, on the date of such purchase, lease or acquisition, plus the book value on said date of all real property held by the company, exclusive of real estate acquired for the convenient accommodation in the transaction of its business and real estate held pursuant to chapter one hundred and twenty-one A would exceed twenty per centum of its assets.