; (ii) the speed of broadband service; (iii) the average price of broadband service in a proposed service area; (iv) any changes in broadband service adoption rates, including new subscribers generated from demand-side projects; and (v) any other metrics the Secretary determines to be appropriate. (2) Additional reporting The Secretary may require any additional reporting and information by any recipient of a grant under this section so as to ensure compliance with this section. (c) Audits The Inspector General, Department of Agriculture, shall conduct annual audits of the grant program provided for in this section, and shall direct the Secretary to implement such recommendations as the Inspector General finds necessary to ensure that the funds made available under subsection (f) are used properly and efficiently. (d) GAO reports The Comptroller General of the United States shall submit to the Secretary annual reports that assess the progress and level of success of the grant program provided for in this section. (e) Annual reports to the Congress The Secretary shall submit an annual report to the Committee on Agriculture and the Committee on Energy and Commerce of the House of Representatives and the Committee on Agriculture, Nutrition, and Forestry and the Committee on Commerce, Science, and Transportation of the Senate on how the grant funds provided under subsection (a) were used by the recipients, how many households, businesses, community centers, and critical community facilities received broadband service as a result of the grants, in which regions the broadband service was provided, how many applications for the grants were denied, and how many of the grants were provided. (f) Limitations on authorization of appropriations To carry out this section, there are authorized to be appropriated to the Secretary $100,000,000 for each of fiscal years 2019 through 2023, to remain available until expended, not less than 90 percent of which shall be available for grants under subsection (a).