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:
Joe Armstrong (actor)
Table title:
Theatre
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Play </th><th colspan=1 rowspan=1 > Playwright </th><th colspan=1 rowspan=1 > Role </th><th colspan=1 rowspan=1 > Theatre </th><th colspan=1 rowspan=1 > Notes </th></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 1998 </td><td class="highlighted"  colspan=1 rowspan=1 > Dancing at Lughnasa </td><td colspan=1 rowspan=1 > Brian Friel </td><td class="highlighted"  colspan=1 rowspan=1 > Gerry Evans </td><td colspan=1 rowspan=1 > George Square Theatre, Edinburgh Arts Theatre, London </td><td class="highlighted"  colspan=1 rowspan=1 > National Youth Theatre </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > 2000 </td><td class="highlighted"  colspan=1 rowspan=1 > They Shoot Horses, Don't They? </td><td colspan=1 rowspan=1 > Ray Herman </td><td class="highlighted"  colspan=1 rowspan=1 > Lieutenant Stedna </td><td colspan=1 rowspan=1 > Apollo Theatre, London </td><td class="highlighted"  colspan=1 rowspan=1 > National Youth Theatre </td></tr>
<tr> <td colspan=1 rowspan=1 > 2003 </td><td colspan=1 rowspan=1 > Protection </td><td colspan=1 rowspan=1 > Fin Kennedy </td><td colspan=1 rowspan=1 > Adam Jeff </td><td colspan=1 rowspan=1 > Soho Theatre, London </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2004 </td><td colspan=1 rowspan=1 > How Love Is Spelt </td><td colspan=1 rowspan=1 > Chloe Moss </td><td colspan=1 rowspan=1 > Joe </td><td colspan=1 rowspan=1 > Bush Theatre, London </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2005 </td><td colspan=1 rowspan=1 > A Night at the Dogs </td><td colspan=1 rowspan=1 > Matt Charman </td><td colspan=1 rowspan=1 > Danny </td><td colspan=1 rowspan=1 > Soho Theatre, London </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2009 </td><td colspan=1 rowspan=1 > Orphans </td><td colspan=1 rowspan=1 > Dennis Kelly </td><td colspan=1 rowspan=1 > Liam </td><td colspan=1 rowspan=1 > Traverse Theatre, Edinburgh Birmingham Repertory Theatre Soho Theatre, London </td><td colspan=1 rowspan=1 > Nominated: Stage Award for Best Actor </td></tr>
<tr> <td colspan=1 rowspan=1 > 2010 </td><td colspan=1 rowspan=1 > The Empire </td><td colspan=1 rowspan=1 > DC Moore </td><td colspan=1 rowspan=1 > Gary </td><td colspan=1 rowspan=1 > Jerwood Theatre Upstairs, London Drum Theatre, Plymouth </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2011 </td><td colspan=1 rowspan=1 > Flare Path </td><td colspan=1 rowspan=1 > Terence Rattigan </td><td colspan=1 rowspan=1 > Sergeant Dusty Miller </td><td colspan=1 rowspan=1 > Theatre Royal Haymarket, London </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2012 </td><td colspan=1 rowspan=1 > Miss Julie </td><td colspan=1 rowspan=1 > August Strindberg </td><td colspan=1 rowspan=1 > Jean </td><td colspan=1 rowspan=1 > Royal Exchange Theatre, Manchester </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2013 </td><td colspan=1 rowspan=1 > The Dumb Waiter </td><td colspan=1 rowspan=1 > Harold Pinter </td><td colspan=1 rowspan=1 > Gus </td><td colspan=1 rowspan=1 > The Print Room, London </td><td colspan=1 rowspan=1 > Nominated: Offie Award for Best Male Performance </td></tr>
<tr> <td colspan=1 rowspan=1 > 2015 </td><td colspan=1 rowspan=1 > Constellations </td><td colspan=1 rowspan=1 > Nick Payne </td><td colspan=1 rowspan=1 > Roland </td><td colspan=1 rowspan=1 > Touring production </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 > 2015 </td><td colspan=1 rowspan=1 > Husbands & Sons </td><td colspan=1 rowspan=1 > D H Lawrence </td><td colspan=1 rowspan=1 > Luther Gascoigne </td><td colspan=1 rowspan=1 > Co-production between National Theatre,London and Royal Exchange, Manchester </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
What roles did Joe Armstrong play with the National Youth Theatre?
Answer:
Armstrong played as Gerry Evans in Dancing at Lughnasa in 1998 and Lieutenant Stedna in They Shoot Horses, Don't They? in 2000 at the National Youth Theatre.