We appreciate you choosing TurboTax,
The line 15000 on your wife's tax return shows her gross income, which is her income before deductions. In addition to her wages and salary from your T4 - Statement of Remuneration Paid, it includes income that she may have received from other sources. Her annual income is often more than just what she is paid hourly or annually by her employer.
When you don’t know your spouse’s income and can’t find out through reasonable means, enter your best estimate. You can return to this question and edit the amount after you finish filling your wife's return and have the correct answer.
Please visit the link provided for further clarifications:
TurboTax FAQ: What if I don't know my spouse's income?