Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| School Year | Class A | Class AA | Class AAA | Class AAAA | Class AAAAA |
| --- | --- | --- | --- | --- | --- |
| 1990-91 | Valley Mills | Canadian | Lampasas | Waco Midway | Lubbock |
| 1991-92 | Valley Mills | Canadian | Troy | Highland Park | Lubbock |
| 1992-93 | Lindsay | Wimberley | Seminole | Kingsville | San Antonio Holmes |
| 1993-94 | Lindsay | Canadian | Cuero | North Lamar | Fort Worth Dunbar |
| 1994-95 | Lindsay | Troup | Waco Connally | North Lamar | Plano |
| 1995-96 | Rule | Canadian | Wimberley | Austin Johnson | Houston Bellaire |
| 1996-97 | Vega | Stinnett West Texas | Bridgeport | Waco Midway | Humble |
| 1997-98 | Moulton | Stinnett West Texas | Wimberley | Highland Park | Humble |
| 1998-99 | Lenorah Grady | Lindsay | Wimberley | Highland Park | Arlington Lamar |
| 1999-2000 | Hedley | Stinnett West Texas | Bridgeport | Gregory-Portland | Houston Bellaire |
| 2000-01 | Lenorah Grady | Seymour | Bridgeport | Carthage | Arlington Lamar |
| 2001-02 | (tie) Sudan/Vega | Argyle | Seminole | Fredericksburg | South Texas Science Academy |
| 2002-03 | Port Aransas | Argyle | Wimberley | Jacksonville | Fort Bend Hightower |
| 2003-04 | Vega | Argyle | Ballinger | Wichita Falls | Katy Taylor |
| 2004-05 | Kingsville Academy | Argyle | Wimberley | Friendswood | Sugar Land Clements |
| 2005-06 | Garden City | Argyle | Cuero | Highland Park | Sugar Land Clements |
| 2006-07 | Garden City | Floydada | Cuero | Highland Park | Sugar Land Clements |
| 2007-08 | Harper | Floydada | Argyle | Highland Park | Sugar Land Clements |
| 2008-09 | Lindsay | (tie) North Hills School Irving/White Oak | Whitney | Highland Park | Sugar Land Dulles |
| 2009-10 | Canadian | North Hills School Irving | (tie) La Feria/Whitney | Highland Park | Sugar Land Clements |
| 2010-11 | Avery | Whitney | La Feria | Highland Park | Fort Worth Paschal |
| 2011-12 | Valley View | Whitney | La Feria | Highland Park | Sugar Land Dulles |
Question:
What are all the school years where class AAAA is in Gregory-Portland? 
Answer:
1999-2000