A taxpayer retires this year and receives the first payment on an annuity that was purchased several years ago. The taxpayer's investment in the annuity is $75,000, and the annuity pays $10,000 per year for the remainder of the taxpayer's life. Based on IRS Mortality Tables, the taxpayer is expected to live another twenty years. If the taxpayer receives $4,000 in annuity payments in the current year, the nontaxable portion calculated using the general rule is what?