I cross checked the datatype of the table value by using the below line. ATTRITION_RATE column data was double type..
System.Type type2 = ds.Tables[0].Rows[0][2].GetType();
List<Yearly> yearly = dataset.Tables[0].AsEnumerable()
.Select(row => new Yearly
{
Yearly_Rate = row.Field<double>("ATTRITION_RATE"),
Total_EmpCount = row.Field<int>("TOTAL_EMP"),
Resigned_EmpCount = row.Field<int>("RESIGNED_EMP")
}).ToList();
casted the data accordingly, it is working