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 of victory | Course | Location | Purse ( $ ) | Winners share ($) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2013.0 | Zach Johnson | United States | 64-70-69-65=268 | –16 | 2 strokes | Conway Farms Golf Club | Lake Forest, Illinois | 8000000.0 | 1440000.0 |
| 2012.0 | Rory McIlroy | Northern Ireland | 64-68-69-67=268 | –20 | 2 strokes | Crooked Stick Golf Club | Carmel, Indiana | 8000000.0 | 1440000.0 |
| 2011.0 | Justin Rose | England | 63-68-69-71=271 | –13 | 2 strokes | Cog Hill Golf & Country Club | Lemont, Illinois | 8000000.0 | 1440000.0 |
| 2010.0 | Dustin Johnson | United States | 68-70-68-69=275 | –9 | 1 stroke | Cog Hill Golf & Country Club | Lemont, Illinois | 7500000.0 | 1350000.0 |
| 2009.0 | Tiger Woods (2) | United States | 68-67-62-68=265 | –19 | 8 strokes | Cog Hill Golf & Country Club | Lemont, Illinois | 7500000.0 | 1350000.0 |
| 2008.0 | Camilo Villegas | Colombia | 65-66-66-68=265 | –15 | 2 strokes | Bellerive Country Club | Town and Country, Missouri | 7000000.0 | 1260000.0 |
Question:
What was zach johnson's score to par?
Answer:
–16