How to import decimal values from Excel to nvarchar column correctly?

I have SQL Server 2012 Integration Services. I have Excel Source and OLE DB Destination.

I have 2 Excels, both having exactly same columns and their destination table is same.

I have MarketShare column in Excel. I have also MarketShare column nvarchar(100) in Database. I should not make any change in Excel file or DB table.

MarketShare value can be numerical like "0.50" or "25.4" or text like "Not Available" or text like "Not Available Yet" 

My problem is that numerical values are stored to DB like 0.500000000000003, 25.399999999999999. Text as stored correctly.

What should I do so that digits of numerical values are stored corretly to nvarchar(100) column?

Kenny_I