The working income tax benefit (WITB) is a refundable tax credit in Canada, similar to the Earned Income Tax Credit (EITC) in the United States. Introduced in 2007, it offers tax relief to working low-income individuals and encourages others to enter the workforce. The WITB has been expanded considerably since its introduction.

Based on this passage, when did the working income tax benefit come into effect? Let's think fast. Stream of consciousness:
To answer the question, consider the following: Introduced in 2007, it offers tax relief to working low-income individuals and encourages others to enter the workforce. So the final answer is 2007.