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:
1977 Egyptian protection of national unity referendum
Table title:
Results
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Choice </th><th colspan=1 rowspan=1 > Votes </th><th colspan=1 rowspan=1 > % </th></tr>
<tr> <td colspan=1 rowspan=1 > For </td><td colspan=1 rowspan=1 > 9,166,179 </td><td class="highlighted"  colspan=1 rowspan=1 > 99.4 </td></tr>
<tr> <td colspan=1 rowspan=1 > Against </td><td colspan=1 rowspan=1 > 54,138 </td><td colspan=1 rowspan=1 > 0.6 </td></tr>
<tr> <td colspan=1 rowspan=1 > Invalid/blank votes </td><td colspan=1 rowspan=1 > 27,420 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Total </td><td colspan=1 rowspan=1 > 9,247,737 </td><td colspan=1 rowspan=1 > 100 </td></tr>
<tr> <td colspan=1 rowspan=1 > Registered voters/turnout </td><td colspan=1 rowspan=1 > 9,564,482 </td><td class="highlighted"  colspan=1 rowspan=1 > 96.7 </td></tr>
<tr> <td colspan=3 rowspan=1 > Source: Nohlen et al. </td></tr>
</table>
Question:
How percent voters approved the 1977 Egyptian protection of national unity referendum ?
Answer:
The 1977 Egyptian protection of national unity referendum was approved by 99.4% of voters, with a turnout of 96.7%.