What are the numbers for that appear on the right side of a system error page ?

Hi;
What do the numbers on the right side of the Stack Track section of the system generated error page for ? 
For instance :
System.Web.UI.Control.DataBind(Boolean raiseOnDataBinding) +216
   System.Web.UI.Control.DataBind() +12
   System.Web.UI.Control.DataBindChildren() +204
 
Thanks

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