Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Professors in the United States
Table title:
Salary
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=2 > Rank </th><th colspan=1 rowspan=2 > Lowest median by field </th><th colspan=1 rowspan=2 > Highest median by field </th><th colspan=1 rowspan=2 > Overall median </th><th colspan=1 rowspan=2 > Common range </th><th colspan=2 rowspan=1 > Common salary range in relation to labor force </th></tr>
<tr> <th colspan=1 rowspan=1 > Full-time, age 25+ </th><th colspan=1 rowspan=1 > All earners age 25+ </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Assistant professor </td><td colspan=1 rowspan=1 > $45,927 </td><td colspan=1 rowspan=1 > $81,005 </td><td class="highlighted"  colspan=1 rowspan=1 > $58,662 </td><td colspan=1 rowspan=1 > Low 50s – Low 60s </td><td colspan=1 rowspan=1 > 70th to 75th percentile </td><td colspan=1 rowspan=1 > 77th to 83rd percentile </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Associate professor </td><td colspan=1 rowspan=1 > $56,943 </td><td colspan=1 rowspan=1 > $98,530 </td><td class="highlighted"  colspan=1 rowspan=1 > $69,911 </td><td colspan=1 rowspan=1 > Low 60s – High 70s </td><td colspan=1 rowspan=1 > 75th to 86th percentile </td><td colspan=1 rowspan=1 > 83rd to 87th percentile </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Full professor </td><td colspan=1 rowspan=1 > $68,214 </td><td colspan=1 rowspan=1 > $136,634 </td><td class="highlighted"  colspan=1 rowspan=1 > $98,974 </td><td colspan=1 rowspan=1 > High 70s – Low 100s Mid 100s at Elite Universities </td><td colspan=1 rowspan=1 > 86th to 91st percentile 96th percentile </td><td colspan=1 rowspan=1 > 87th to 91st percentile 97th percentile </td></tr>
</table>
Question:
When was the average salary $98,974 for professors, and what were the average salaries for associate professors and assistant professors that year?
Answer:
The average salary in the 2005-2006 academic year was $98,974 for professors, $69,911 for associate professors, and $58,662 for assistant professors.