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 Prime Ministers of Niger
Table title:
List
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=2 > No. </th><th colspan=1 rowspan=2 > Prime Minister (Birth–Death) </th><th colspan=1 rowspan=2 > Portrait </th><th colspan=3 rowspan=1 > Tenure </th><th colspan=2 rowspan=2 > Political affiliation </th><th colspan=1 rowspan=2 > Head(s) of State </th></tr>
<tr> <th colspan=1 rowspan=1 > Took office </th><th colspan=1 rowspan=1 > Left office </th><th colspan=1 rowspan=1 > Time in office </th></tr>
<tr> <th colspan=1 rowspan=1 > 1 </th><th class="highlighted"  colspan=1 rowspan=1 > Mamane Oumarou (1946–) </th><td colspan=1 rowspan=1 > - </td><td class="highlighted"  colspan=1 rowspan=1 > 24 January 1983 </td><td colspan=1 rowspan=1 > 14 November 1983 </td><td colspan=1 rowspan=1 > 294 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > Independent </td><td colspan=1 rowspan=1 > Kountché </td></tr>
<tr> <th colspan=1 rowspan=1 > 2 </th><th colspan=1 rowspan=1 > Hamid Algabid (1941–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 14 November 1983 </td><td colspan=1 rowspan=1 > 15 July 1988 </td><td colspan=1 rowspan=1 > 4 years, 244 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > Independent </td><td colspan=1 rowspan=1 > Kountché Saibou </td></tr>
<tr> <th colspan=1 rowspan=1 > (1) </th><th class="highlighted"  colspan=1 rowspan=1 > Mamane Oumarou (1946–) </th><td colspan=1 rowspan=1 > - </td><td class="highlighted"  colspan=1 rowspan=1 > 15 July 1988 </td><td colspan=1 rowspan=1 > 20 December 1989 </td><td colspan=1 rowspan=1 > 1 year, 158 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > MNSD–Nassara </td><td colspan=1 rowspan=1 > Saibou </td></tr>
<tr> <td colspan=9 rowspan=1 > Post abolished (20 December 1989 – 2 March 1990) </td></tr>
<tr> <th colspan=1 rowspan=1 > 3 </th><th colspan=1 rowspan=1 > Aliou Mahamidou (1936–1996) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 2 March 1990 </td><td colspan=1 rowspan=1 > 27 October 1991 </td><td colspan=1 rowspan=1 > 1 year, 239 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > MNSD–Nassara </td><td colspan=1 rowspan=1 > Saibou </td></tr>
<tr> <th colspan=1 rowspan=1 > 4 </th><th colspan=1 rowspan=1 > Amadou Cheiffou (1942–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 27 October 1991 </td><td colspan=1 rowspan=1 > 17 April 1993 </td><td colspan=1 rowspan=1 > 1 year, 172 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > Independent </td><td colspan=1 rowspan=1 > Saibou Ousmane </td></tr>
<tr> <th colspan=1 rowspan=1 > 5 </th><th colspan=1 rowspan=1 > Mahamadou Issoufou (1951–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 17 April 1993 </td><td colspan=1 rowspan=1 > 28 September 1994 </td><td colspan=1 rowspan=1 > 1 year, 164 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > PNDS–Tarayya </td><td colspan=1 rowspan=1 > Ousmane </td></tr>
<tr> <th colspan=1 rowspan=1 > 6 </th><th colspan=1 rowspan=1 > Souley Abdoulaye (1965–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 28 September 1994 </td><td colspan=1 rowspan=1 > 8 February 1995 </td><td colspan=1 rowspan=1 > 133 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > CSD–Rahama </td><td colspan=1 rowspan=1 > Ousmane </td></tr>
<tr> <th colspan=1 rowspan=1 > 7 </th><th colspan=1 rowspan=1 > Amadou Cissé (1948–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 8 February 1995 </td><td colspan=1 rowspan=1 > 21 February 1995 </td><td colspan=1 rowspan=1 > 13 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > Independent </td><td colspan=1 rowspan=1 > Ousmane </td></tr>
<tr> <th colspan=1 rowspan=1 > 8 </th><th colspan=1 rowspan=1 > Hama Amadou (1949–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 21 February 1995 </td><td colspan=1 rowspan=1 > 27 January 1996 (deposed.) </td><td colspan=1 rowspan=1 > 340 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > MNSD–Nassara </td><td colspan=1 rowspan=1 > Ousmane </td></tr>
<tr> <td colspan=9 rowspan=1 > Post vacant (27 – 30 January 1996) </td></tr>
<tr> <th colspan=1 rowspan=1 > 9 </th><th colspan=1 rowspan=1 > Boukary Adji (1939–2018) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 30 January 1996 </td><td colspan=1 rowspan=1 > 21 December 1996 </td><td colspan=1 rowspan=1 > 326 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > Independent </td><td colspan=1 rowspan=1 > Maïnassara </td></tr>
<tr> <th colspan=1 rowspan=1 > (7) </th><th colspan=1 rowspan=1 > Amadou Cissé (1948–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 21 December 1996 </td><td colspan=1 rowspan=1 > 27 November 1997 </td><td colspan=1 rowspan=1 > 341 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > Independent </td><td colspan=1 rowspan=1 > Maïnassara </td></tr>
<tr> <th colspan=1 rowspan=1 > 10 </th><th colspan=1 rowspan=1 > Ibrahim Hassane Mayaki (1951–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 27 November 1997 </td><td colspan=1 rowspan=1 > 1 January 2000 </td><td colspan=1 rowspan=1 > 2 years, 35 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > RDP–Jama'a </td><td colspan=1 rowspan=1 > Maïnassara Wanké Tandja </td></tr>
<tr> <th colspan=1 rowspan=1 > (8) </th><th colspan=1 rowspan=1 > Hama Amadou (1949–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 1 January 2000 </td><td colspan=1 rowspan=1 > 7 June 2007 </td><td colspan=1 rowspan=1 > 7 years, 157 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > MNSD–Nassara </td><td colspan=1 rowspan=1 > Tandja </td></tr>
<tr> <th colspan=1 rowspan=1 > 11 </th><th colspan=1 rowspan=1 > Seyni Oumarou (1951–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 7 June 2007 </td><td colspan=1 rowspan=1 > 23 September 2009 </td><td colspan=1 rowspan=1 > 2 years, 108 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > MNSD–Nassara </td><td colspan=1 rowspan=1 > Tandja </td></tr>
<tr> <td colspan=1 rowspan=1 > – </td><td colspan=1 rowspan=1 > Albadé Abouba </td><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 23 September 2009 </td><td colspan=1 rowspan=1 > 2 October 2009 </td><td colspan=1 rowspan=1 > 9 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > MNSD–Nassara </td><td colspan=1 rowspan=1 > Tandja </td></tr>
<tr> <th colspan=1 rowspan=1 > 12 </th><th colspan=1 rowspan=1 > Ali Badjo Gamatié </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 2 October 2009 </td><td colspan=1 rowspan=1 > 18 February 2010 (deposed.) </td><td colspan=1 rowspan=1 > 139 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > MNSD–Nassara </td><td colspan=1 rowspan=1 > Tandja </td></tr>
<tr> <td colspan=9 rowspan=1 > Post vacant (18 – 23 February 2010) </td></tr>
<tr> <th colspan=1 rowspan=1 > 13 </th><th colspan=1 rowspan=1 > Mahamadou Danda (1951–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 23 February 2010 </td><td colspan=1 rowspan=1 > 7 April 2011 </td><td colspan=1 rowspan=1 > 1 year, 43 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > Independent </td><td colspan=1 rowspan=1 > Djibo </td></tr>
<tr> <th colspan=1 rowspan=1 > 14 </th><th colspan=1 rowspan=1 > Brigi Rafini (1953–) </th><td colspan=1 rowspan=1 > - </td><td colspan=1 rowspan=1 > 7 April 2011 </td><td colspan=1 rowspan=1 > Incumbent </td><td colspan=1 rowspan=1 > 8 years, 19 days </td><th colspan=1 rowspan=1 >  </th><td colspan=1 rowspan=1 > PNDS–Tarayya </td><td colspan=1 rowspan=1 > Issoufou </td></tr>
</table>
Question:
How many periods did Mamane Oumarou (born 1946) serve as Prime Minister of Niger, and what decade were those periods in?
Answer:
Mamane Oumarou (born 1946) served two periods as Prime Minister of Niger during the 1980s.