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 | Joined |
| --- | --- | --- | --- | --- | --- | --- |
| Agnes Scott College † | Decatur, Georgia | Scottish Terriers | 1889.0 | Private/Presbyterian | 914.0 | 2002.0 |
| Pine Manor College † | Chestnut Hill, Massachusetts | Gators | 1911.0 | Private/Non-sectarian | 480.0 | 2012.0 |
| Salem College † | Winston-Salem, North Carolina | Spirits | 1772.0 | Private/Non-sectarian | 1100.0 | 2009.0 |
| Trinity Washington University † | Washington, D.C. | Tigers | 1897.0 | Private/Catholic | 2100.0 | 2012.0 |
| Wesleyan College † | Macon, Georgia | Pioneers | 1839.0 | Private/Methodist | 645.0 | 2003.0 |
| Finlandia University ^* | Hancock, Michigan | Lions | 1896.0 | Private/Lutheran | 500.0 | 2013.0 |
| University of Maine at Presque Isle ^ | Presque Isle, Maine | Owls | 1903.0 | Public | 1600.0 | 2013.0 |
Question:
On how many different dates did schools from Chestnut Hill, Massachusetts join the conference?
Answer:
1.0