Step 1 :Create a list for each column: Withholding, Employee's Social Security, and Medicare for all employees.
Step 2 :The lists are: withholding = [179, 145, 77], social_security = [120.4, 98.02, 89.59], medicare = [28.16, 22.92, 20.95].
Step 3 :Calculate the total for each category: total_withholding = 401, total_social_security = 308.01, total_medicare = 72.03.
Step 4 :Calculate the total deposit by adding the totals of each category: total_deposit = total_withholding + total_social_security + total_medicare.
Step 5 :The total deposit is 781.04.
Step 6 :The employer's deposit is \(\boxed{781.04}\).