31.1. For the purposes of sections 27, 30 and 31, any company which, for its fiscal year beginning in 1983, obtained on its common shares a yield of at least 4% of their book value or paid on its common shares a dividend of at least 4% of their book value is deemed to have obtained on its common shares a net yield of at least 4% of their book value for the fiscal years beginning or ending in 1981 and 1982.