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:
Una-class submarine
Table title:
Boats
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Name </th><th colspan=1 rowspan=1 > Pennant number </th><th colspan=1 rowspan=1 > Namesake </th><th colspan=1 rowspan=1 > Builder </th><th colspan=1 rowspan=1 > Completed </th><th colspan=1 rowspan=1 > Decommissioned </th><th colspan=1 rowspan=1 > Fate </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Tisa </td><td class="highlighted"  colspan=1 rowspan=1 > P-911 </td><td colspan=1 rowspan=1 > Tisa </td><td class="highlighted"  colspan=1 rowspan=6 > Brodogradilište specijalnih objekata, Split, SR Croatia, SFR Yugoslavia </td><td class="highlighted"  colspan=1 rowspan=1 > 1985 </td><td colspan=1 rowspan=1 > 1997/2001 </td><td colspan=1 rowspan=1 > extant; to be donated to the Museum of Science and Technology in Belgrade, Serbia. The submarine was delivered to Belgrade in June 2018. </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Una </td><td class="highlighted"  colspan=1 rowspan=1 > P-912 </td><td colspan=1 rowspan=1 > Una </td><td class="highlighted"  colspan=1 rowspan=1 > 1986 </td><td colspan=1 rowspan=1 > 1997/2001 </td><td colspan=1 rowspan=1 > extant; Porto Montenegro Museum, Montenegro. </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Zeta </td><td class="highlighted"  colspan=1 rowspan=1 > P-913 </td><td colspan=1 rowspan=1 > Zeta </td><td class="highlighted"  colspan=1 rowspan=1 > 1987 </td><td colspan=1 rowspan=1 > 2005 </td><td colspan=1 rowspan=1 > extant; Pivka Military History Park, Slovenia. </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Soča </td><td class="highlighted"  colspan=1 rowspan=1 > P-914 </td><td colspan=1 rowspan=1 > Soča </td><td class="highlighted"  colspan=1 rowspan=1 > 1987 </td><td colspan=1 rowspan=1 > 2001/2005 </td><td colspan=1 rowspan=1 > extant; to be donated to a museum </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Kupa </td><td class="highlighted"  colspan=1 rowspan=1 > P-915 </td><td colspan=1 rowspan=1 > Kupa </td><td class="highlighted"  colspan=1 rowspan=1 > 1989 </td><td colspan=1 rowspan=1 > 2003 </td><td colspan=1 rowspan=1 > scrapped in 2008 </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > Vardar </td><td class="highlighted"  colspan=1 rowspan=1 > P-916 </td><td colspan=1 rowspan=1 > Vardar </td><td class="highlighted"  colspan=1 rowspan=1 > 1989 </td><td colspan=1 rowspan=1 > 2005 </td><td colspan=1 rowspan=1 > fate unknown (sighted 2 May 2018 on the pier at Pristan Naval Base, Pomorska Baza Pristan, Montenegro, with one other sub of same class) </td></tr>
</table>
Question:
What was the time duration for which the six boats were completed at the Brodogradilište Specijalnih Objekata (BSO) in Split, SR Croatia?
Answer:
All six boats were completed from 1985 to 1989 at the Brodogradilište Specijalnih Objekata (BSO) in Split, SR Croatia.