Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Property Taxes | Investment Earnings | Other Local Sources | State & Federal | Total Revenue |
| --- | --- | --- | --- | --- | --- |
| 2005.0 | $24,384,901 | $255,041 | $2,670,060 | $13,581,968 | $40,891,700 |
| 2004.0 | 21,099,214 | 181,103 | 2,624,131 | 13,999,169 | 37,903,617 |
| 2003.0 | 17,199,210 | 509,862 | 2,309,087 | 12,794,922 | 32,539,572 |
| 2002.0 | 14,359,199 | 879,398 | 2,168,096 | 15,132,879 | 32,539,572 |
| 2001.0 | 11,631,227 | 1,949,885 | 1,987,436 | 12,929,489 | 28,498,037 |
| 2000.0 | 10,608,734 | 493,839 | 2,127,480 | 8,549,565 | 21,779,618 |
Question:
What were the investment earnings in a year when total revenue was $21,779,618?
Answer:
493839.0