The Ratio of Labour Income to Total Income Labour income has stayed in the 0.67 to 0.62 range of total income over a long period of time, although it has fallen slightly over the years. This approximate constancy of factor shares is evidence for the Cobb-Douglas production function. (This figure is produced from Canadian national accounts data. Labour income is wages. Total income is the sum of labour income (498076), corporate profits before taxes (498077), interest and investment income (498079), and capital consumption allowances (498084)).