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:
List of Mayors of Jaffna
Table title:
Mayors and chairmen
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=2 rowspan=1 > Name </th><th colspan=1 rowspan=1 > Party </th><th colspan=1 rowspan=1 > Took office </th><th colspan=1 rowspan=1 > Left office </th><th colspan=1 rowspan=1 > Title </th><th colspan=1 rowspan=1 > Refs </th></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Canagaratnam, A.A. Canagaratnam </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=4 > Chairman </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Nalliah, R. R.R. R. Nalliah </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=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Sabapathy, Sam A.Sam A. Sabapathy </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 1937 </td><td colspan=1 rowspan=1 > 1939 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Aiyadurai, K.K. Aiyadurai </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 1942 </td><td colspan=1 rowspan=1 > 1943 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Sabapathy, Sam A.Sam A. Sabapathy </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 6 January 1949 </td><td colspan=1 rowspan=1 > 31 December 1949 </td><td colspan=1 rowspan=22 > Mayor </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Ponnambalam, CathiraveluCathiravelu Ponnambalam </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 6 January 1950 </td><td colspan=1 rowspan=1 > 31 December 1951 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Sabapathy, Sam A.Sam A. Sabapathy </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 11 January 1952 </td><td colspan=1 rowspan=1 > 31 December 1954 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Sultan, M. A. M. M.M. A. M. M. Sultan </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 5 January 1955 </td><td colspan=1 rowspan=1 > 31 December 1955 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Navaratnam, S. A.S. A. Navaratnam </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 16 January 1956 </td><td colspan=1 rowspan=1 > 31 December 1957 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Kasipillai, P.P. Kasipillai </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 6 July 1960 </td><td colspan=1 rowspan=1 > 31 December 1960 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Thurairajah, T. S.T. S. Thurairajah </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 7 January 1961 </td><td colspan=1 rowspan=1 > 12 February 1962 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Jacob, M.M. Jacob </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 19 February 1962 </td><td colspan=1 rowspan=1 > 15 May 1963 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Tharmalingam, S. A.S. A. Tharmalingam </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 28 May 1962 </td><td colspan=1 rowspan=1 > 4 April 1963 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > John, P. M.P. M. John </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 11 April 1963 </td><td colspan=1 rowspan=1 > 6 May 1963 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Thurairajah, T. S.T. S. Thurairajah </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 15 May 1963 </td><td colspan=1 rowspan=1 > 6 May 1963 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Mahadeva, S. S.S. S. Mahadeva </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 8 July 1965 </td><td colspan=1 rowspan=1 > 31 December 1965 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Nagarajah, S.S. Nagarajah </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 8 January 1966 </td><td colspan=1 rowspan=1 > 24 March 1966 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Duraiappah, AlfredAlfred Duraiappah </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 15 February 1970 </td><td colspan=1 rowspan=1 > 21 April 1971 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Duraiappah, AlfredAlfred Duraiappah </td><td colspan=1 rowspan=1 > Sri Lanka Freedom Party </td><td colspan=1 rowspan=1 > 22 April 1971 </td><td colspan=1 rowspan=1 > 27 July 1975 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Viswanathan, R.R. Viswanathan </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 1 June 1979 </td><td colspan=1 rowspan=1 > 31 May 1983 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td class="highlighted"  colspan=1 rowspan=1 > Yogeswaran, SarojiniSarojini Yogeswaran </td><td class="highlighted"  colspan=1 rowspan=1 > Tamil United Liberation Front </td><td colspan=1 rowspan=1 > 11 March 1998 </td><td class="highlighted"  colspan=1 rowspan=1 > 17 May 1998 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td class="highlighted"  colspan=1 rowspan=1 > Sivapalan, PonPon Sivapalan </td><td class="highlighted"  colspan=1 rowspan=1 > Tamil United Liberation Front </td><td colspan=1 rowspan=1 > 29 June 1998 </td><td class="highlighted"  colspan=1 rowspan=1 > 11 September 1998 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Raviraj, NadarajahNadarajah Raviraj </td><td colspan=1 rowspan=1 > Tamil United Liberation Front </td><td colspan=1 rowspan=1 > 9 January 2001 </td><td colspan=1 rowspan=1 > 18 December 2001 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Kandaiyan, SellanSellan Kandaiyan </td><td colspan=1 rowspan=1 > Tamil United Liberation Front </td><td colspan=1 rowspan=1 > 15 January 2002 </td><td colspan=1 rowspan=1 > 13 February 2003 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Patkunarajah, YogeswariYogeswari Patkunarajah </td><td colspan=1 rowspan=1 > Eelam People's Democratic Party </td><td colspan=1 rowspan=1 > 1 September 2009 </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Arnold, E.E. Arnold </td><td colspan=1 rowspan=1 > Illankai Tamil Arasu Kachchi </td><td colspan=1 rowspan=1 > 26 February 2018 </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
When did the first two mayors from the Tamil United Liberation Front leave office?
Answer:
The Tamil United Liberation Front Mayor of Jaffna Sarojini Yogeswaran left office on 17 May 1998 and her successor Pon Sivapalan left office on 11 September 1998.