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:
1936 United States presidential election in Oklahoma
Table title:
Results
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=2 rowspan=1 > Party </th><th colspan=1 rowspan=1 > Candidate </th><th colspan=1 rowspan=1 > Votes </th><th colspan=1 rowspan=1 > % </th></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Democratic </td><td class="highlighted"  colspan=1 rowspan=1 > Franklin D. Roosevelt (inc.) </td><td colspan=1 rowspan=1 > 501,069 </td><td class="highlighted"  colspan=1 rowspan=1 > 66.83% </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Republican </td><td class="highlighted"  colspan=1 rowspan=1 > Alf Landon </td><td colspan=1 rowspan=1 > 245,122 </td><td class="highlighted"  colspan=1 rowspan=1 > 32.69% </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Socialist </td><td colspan=1 rowspan=1 > Norman Thomas </td><td colspan=1 rowspan=1 > 2,221 </td><td colspan=1 rowspan=1 > 0.30% </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Prohibition </td><td colspan=1 rowspan=1 > D. Leigh Colvin </td><td colspan=1 rowspan=1 > 1,328 </td><td colspan=1 rowspan=1 > 0.18% </td></tr>
<tr> <th colspan=3 rowspan=1 > Total votes </th><td colspan=1 rowspan=1 > 749,740 </td><td colspan=1 rowspan=1 > 100% </td></tr>
</table>
Question:
Who won Oklahoma's 1936 United States presidential election and by what margin of the popular vote did they win?
Answer:
1936 United States presidential election in Oklahoma was won by incumbent President Franklin D. Roosevelt (D–New York), with 66.83% of the popular vote, while Alf Landon secured 32.69% of the popular vote.