Canada’s federal personal income tax came into effect September 20, 1917 with a 4 per cent tax on all income of single people (unmarried persons and widows or widowers without dependent children) over $2,000. For everyone else, the personal exemption was $3,000. In today’s dollars, the exemptions would be worth approximately $33,000 and $50,000, respectively. To be clear, in today’s dollars, the first federal personal income tax exempted the first $33,000 of income for single people and the first $50,000 for everyone else. For reference, the basic personal exemption for 2016 is $11,474.
Here's equivalent NZ data for your edification: