Query syntax

I would like to construct a query that only returns the SUM if the NAME has all three years. Below is the code to create a table and to populate it with sample data. NOTE: the code does not contain a check to determine if the table already exists.

/****** Object:  Table [dbo].[Hexis]    Script Date: 07/08/2013 14:28:43 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[Hexis](
	[IDNo] [bigint] IDENTITY(1,1) NOT NULL,
	[Yr] [int] NULL,
	[Name] [varchar](50) NULL,
	[Amt] [decimal](18, 5) NULL
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO



Insert into dbo.Hexis (Yr,Name,Amt)
select 2009,'Wilmington',5
Union All
select 2010,'Wilmington',5
Union All
select 2011,'Wilmington',5
Union All
select 2009,'Philadelphia',5
Union All
select 2010,'Philadelphia',5
Union All
select 2011,'Baltimore',5
Union All
select 2009,'Wilmington',7
Union All
select 2010,'Wilmington',7
Union All
select 2011,'Wilmington',7
Union All
select 2009,'Philadelphia',7
Union All
select 2010,'Philadelphia',7
Union All
select 2011,'Baltimore',7

Select allOpen in new window

I would like to write a query which returns the sum of the Amt column but only if the Name exists in all three Years (2009, 2010, 2011).

My failed attempt looks like:

Select Name, Sum(Amt) From Hexis
where Yr in (2009,2010,2011)
Group by Name


Thank you in advance for you assistance.

pat