James and Esther Johnson live at 45678 S.W. 112th Street, Homestead, FL 33033.James, who is 67 years old (date of birth 12/14/1949), is retired receiving social security benefits and Esther, who is 66 years old (date of birth 06/11/1950), is also retired but working on a part-time basis. Their social security numbers are 412-34-5670 and 412-34-5671, respectively. The Johnsons had qualifying health care coverage at all times during the tax year.

Annual social security income for Jim is $18,000 (SSA-1099, box 5) and for Esther is $10,800 (SSA-1099, box 5).

Interest received by them from Central Bank is $2,545 (1099-INT, box 1). No income tax withholding was made.

Esther is working part-time as an interior decorator as an employee of Decorating House, a corporation.Her form W-2 shows the following information:

Wages=$15,000.00Federal W/H=$1,500.00Social security wages=$15,000.00Social security W/H=$930.00Medicare wages=$15,000.00Medicare W/H=$217.50

Their itemized deductions are as follows:

1. Mortgage interest on their main home = $8,100
2. Real estate taxes = $5,600
3. Personal property taxes = $185
4. Doctors' expenses unreimbursed by insurance = $5,400
5. Medical insurance premiums for the year = $2,400
6. Prescribed medicine = $1,995
7. Vitamins = $300
8. Total cash contributions to their church, $675.The contributions were made over the course of the year and no individual contribution was greater than $250.
9. Tax preparation fees for their 2015 return, $325, paid in 2016.
10. Lottery tickets bought by Esther during the year, $750.Winnings received, $940 (W-2G, box 1).Income tax withholding on winnings, $35 (W-2G, box 2).

How much of their social security is taxable?