Table design: how to store denormalized Excel data
You will want to add an alternate key/unique constraint upon the combination of Indicator and Year. By virtue of the value being stored at the intersection of Indicator and Year in the spreadsheet, you are only allowed a single value. The new table design would allow you to have as many entries for a given indicator and year unless you explicitly disallow that.

DDL is approximately 

CREATE TABLE dbo.MyTable
(
    Id int IDENTITY(1,1)
,   Indicator varchar(10) NOT NULL
,   Year smallint NOT NULL
,   Value int NOT NULL
,   CONSTRAINT PK_MyTable PRIMARY KEY
(
    Id
)
,   CONSTRAINT AK_MyTable_Indicator_Year UNIQUE
(
    Indicator
,   Year
)
);