How can I map MS SQL datatype numeric(19, 0) to .NET type

I am working on the mapping from MS SQL database to POCO classes:

I have numeric(19, 0), numeric(18, 0), numeric(3, 0), numeric(3, 0).

I am using the EF power tools to generate POCO and all map to decimal .NET C# Type.

But I think it should map to BigInt, Int64, Int32, Int16 etc.