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:
MKTO
Table title:
As lead artist
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=2 > Title </th><th colspan=1 rowspan=2 > Year </th><th colspan=7 rowspan=1 > Peak chart positions </th><th colspan=1 rowspan=2 > Certifications </th><th colspan=1 rowspan=2 > Album </th></tr>
<tr> <th colspan=1 rowspan=1 > AUS </th><th colspan=1 rowspan=1 > CAN </th><th colspan=1 rowspan=1 > NL </th><th colspan=1 rowspan=1 > NZ </th><th colspan=1 rowspan=1 > SWE </th><th colspan=1 rowspan=1 > UK </th><th colspan=1 rowspan=1 > US </th></tr>
<tr> <th colspan=1 rowspan=1 > "Thank You" </th><td colspan=1 rowspan=1 > 2012 </td><td colspan=1 rowspan=1 > 2 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > 37 </td><td colspan=1 rowspan=1 > 7 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > ARIA: 4× Platinum RMNZ: Platinum </td><td class="highlighted"  colspan=1 rowspan=4 > MKTO </td></tr>
<tr> <th class="highlighted"  colspan=1 rowspan=1 > "Classic" </th><td class="highlighted"  colspan=1 rowspan=2 > 2013 </td><td colspan=1 rowspan=1 > 9 </td><td colspan=1 rowspan=1 > 61 </td><td colspan=1 rowspan=1 > 64 </td><td colspan=1 rowspan=1 > 8 </td><td colspan=1 rowspan=1 > 7 </td><td colspan=1 rowspan=1 > 24 </td><td colspan=1 rowspan=1 > 14 </td><td colspan=1 rowspan=1 > ARIA: 3× Platinum BPI: Platinum IFPI SWE: Platinum RMNZ: Platinum RIAA: Platinum </td></tr>
<tr> <th colspan=1 rowspan=1 > "God Only Knows" </th><td colspan=1 rowspan=1 > 11 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > 19 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > ARIA: Platinum RMNZ: Gold </td></tr>
<tr> <th colspan=1 rowspan=1 > "American Dream" </th><td colspan=1 rowspan=1 > 2014 </td><td colspan=1 rowspan=1 > 40 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > 12 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > ARIA: Gold RMNZ: Gold </td></tr>
<tr> <th colspan=1 rowspan=1 > "Bad Girls" </th><td colspan=1 rowspan=1 > 2015 </td><td colspan=1 rowspan=1 > 80 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Bad Girls EP </td></tr>
<tr> <th colspan=1 rowspan=1 > "Hands Off My Heart/Places You Go" </th><td colspan=1 rowspan=2 > 2016 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=3 > Non-album singles </td></tr>
<tr> <th colspan=1 rowspan=1 > "Superstitious" </th><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <th colspan=1 rowspan=1 > "How Can I Forget" </th><td colspan=1 rowspan=1 > 2018 </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 > — </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=20 rowspan=1 > "—" denotes a single that did not chart or was not released. </td></tr>
</table>
Question:
What year did MKTO release their second single "Classic"?
Answer:
MKTO released their second single "Classic" in 2013.