If the bonds of the district deposited with the state treasurer at the end of two years from the date of the adoption of the bondholders' agreement are less than fifty-one per cent of the principal amount of all bonds of the district then outstanding, the bondholders' agreement shall be abrogated and the committee discharged, and the state treasurer shall return any bonds theretofore deposited with him to the respective owners thereof.
A.R.S. § 48-3249