My salary is higher this year than last year, but my W-2 earnings are less this year.

You should ensure that your pre-tax deductions (health insurance, retirement, etc.) have not changed drastically from one year to the next. Check to see if you received any type of bonus in the prior year that would have increased your total gross pay. If you did not receive a bonus in the current year as well, that would make it appear that you earned less in the current year despite having a higher base salary