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:
| Year | Player | Country | Score | To par | Margin\nof victory | Course | Location | Purse ($) | Winner's\nshare ($) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2014 |  |  |  |  |  | Cherry Hills Country Club | Cherry Hills Village, Colorado | 8,000,000 | 1,440,000 |
| 2013 | Zach Johnson | United States | 64-70-69-65=268 | –16 | 2 strokes | Conway Farms Golf Club | Lake Forest, Illinois | 8,000,000 | 1,440,000 |
| 2012 | Rory McIlroy | Northern Ireland | 64-68-69-67=268 | –20 | 2 strokes | Crooked Stick Golf Club | Carmel, Indiana | 8,000,000 | 1,440,000 |
| 2011 | Justin Rose | England | 63-68-69-71=271 | –13 | 2 strokes | Cog Hill Golf & Country Club | Lemont, Illinois | 8,000,000 | 1,440,000 |
| 2010 | Dustin Johnson | United States | 68-70-68-69=275 | –9 | 1 stroke | Cog Hill Golf & Country Club | Lemont, Illinois | 7,500,000 | 1,350,000 |
| 2009 | Tiger Woods (2) | United States | 68-67-62-68=265 | –19 | 8 strokes | Cog Hill Golf & Country Club | Lemont, Illinois | 7,500,000 | 1,350,000 |
| 2008 | Camilo Villegas | Colombia | 65-66-66-68=265 | –15 | 2 strokes | Bellerive Country Club | Town and Country, Missouri | 7,000,000 | 1,260,000 |
| 2007 | Tiger Woods | United States | 67-67-65-63=262 | –22 | 2 strokes | Cog Hill Golf & Country Club | Lemont, Illinois | 7,000,000 | 1,260,000 |
Question:
how many strokes marked the margin of victory for justin rose in 2011?
Answer:
2