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:
| Institution | Location | Nickname | Founded | Type | Enrollment | Football? | Joined |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Bridgewater College | Bridgewater, Virginia | Eagles | 1880.0 | Private | 1690.0 | Yes | 1976.0 |
| Eastern Mennonite University | Harrisonburg, Virginia | Royals | 1917.0 | Private | 998.0 | No | 1976.0 |
| Emory & Henry College | Emory, Virginia | Wasps | 1836.0 | Private | 1000.0 | Yes | 1976.0 |
| Guilford College | Greensboro, North Carolina | Quakers | 1837.0 | Private | 2682.0 | Yes | 1991.0 |
| Hampden–Sydney College ^ | Hampden Sydney, Virginia | Tigers | 1775.0 | Private | 1120.0 | Yes | 1976.0 |
| Hollins University † | Roanoke, Virginia | *None* | 1842.0 | Private | 816.0 | No | 1982.0 |
| Lynchburg College | Lynchburg, Virginia | Fighting Hornets | 1903.0 | Private | 2500.0 | No | 1976.0 |
| Randolph College * | Lynchburg, Virginia | WildCats | 1891.0 | Private | 522.0 | No | 1982.0 |
| Randolph–Macon College | Ashland, Virginia | Yellow Jackets | 1830.0 | Private | 1146.0 | Yes | 1976.0 |
| Roanoke College | Salem, Virginia | Maroons | 1842.0 | Private | 2100.0 | No | 1976.0 |
| Shenandoah University | Winchester, Virginia | Hornets | 1875.0 | Private | 724.0 | Yes | 2012.0 |
| Sweet Briar College † | Sweet Briar, Virginia | Vixens | 1901.0 | Private | 1767.0 | No | 1982.0 |
| Virginia Wesleyan College | Virginia Beach, Virginia | Marlins | 1961.0 | Private | 1446.0 | No | 1989.0 |
Question:
How many values for joined occur at Guilford College?
Answer:
1.0