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:
1994 Group
Table title:
Historical membership
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Institution </th><th colspan=1 rowspan=1 > Location </th><th colspan=1 rowspan=1 > Year joined </th><th colspan=1 rowspan=1 > Year left </th></tr>
<tr> <td colspan=1 rowspan=1 > University of Bath </td><td colspan=1 rowspan=1 > Bath </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2012 </td></tr>
<tr> <td colspan=1 rowspan=1 > Birkbeck, University of London </td><td colspan=1 rowspan=1 > London </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Durham University </td><td colspan=1 rowspan=1 > Durham </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2012 </td></tr>
<tr> <td colspan=1 rowspan=1 > University of East Anglia </td><td colspan=1 rowspan=1 > Norwich </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Essex </td><td colspan=1 rowspan=1 > Wivenhoe (Essex) </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Exeter </td><td colspan=1 rowspan=1 > Exeter </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2012 </td></tr>
<tr> <td colspan=1 rowspan=1 > Goldsmiths, University of London </td><td colspan=1 rowspan=1 > London </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > Institute of Education, University of London </td><td colspan=1 rowspan=1 > London </td><td colspan=1 rowspan=1 > 2009 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Lancaster </td><td colspan=1 rowspan=1 > Lancaster </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Leicester </td><td colspan=1 rowspan=1 > Leicester </td><td colspan=1 rowspan=1 > 2006 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > London School of Economics </td><td colspan=1 rowspan=1 > London </td><td colspan=1 rowspan=1 > 1994 </td><td class="highlighted"  colspan=1 rowspan=1 > 2006 </td></tr>
<tr> <td colspan=1 rowspan=1 > Loughborough University </td><td colspan=1 rowspan=1 > Loughborough </td><td colspan=1 rowspan=1 > 2006 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Manchester Institute of Science and Technology (UMIST) </td><td colspan=1 rowspan=1 > Manchester </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2004 </td></tr>
<tr> <td colspan=1 rowspan=1 > Queen Mary, University of London </td><td colspan=1 rowspan=1 > London </td><td colspan=1 rowspan=1 > 2006 </td><td colspan=1 rowspan=1 > 2012 </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Reading </td><td colspan=1 rowspan=1 > Reading </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2013 </td></tr>
<tr> <td colspan=1 rowspan=1 > Royal Holloway, University of London </td><td colspan=1 rowspan=1 > Egham </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > University of St Andrews </td><td colspan=1 rowspan=1 > St Andrews </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2012 </td></tr>
<tr> <td colspan=1 rowspan=1 > SOAS, University of London </td><td colspan=1 rowspan=1 > London </td><td colspan=1 rowspan=1 > 2006 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Surrey </td><td colspan=1 rowspan=1 > Guildford </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2012 </td></tr>
<tr> <td colspan=1 rowspan=1 > University of Sussex </td><td colspan=1 rowspan=1 > Brighton </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > University of Warwick </td><td colspan=1 rowspan=1 > Coventry </td><td colspan=1 rowspan=1 > 1994 </td><td class="highlighted"  colspan=1 rowspan=1 > 2008 </td></tr>
<tr> <td colspan=1 rowspan=1 > University of York </td><td colspan=1 rowspan=1 > York </td><td colspan=1 rowspan=1 > 1994 </td><td colspan=1 rowspan=1 > 2012 </td></tr>
</table>
Question:
What periods of time has the London School of economics been a member of this historical group?
Answer:
The London School of Economics was also a member of the 1994 Group until 2006 and the University of Warwick until July 2008.