Taxes on dividends

Hi,

Can anyone explain how is possible that there is no withholding tax deduction on dividends from USA based (MLP) master limited partnership companies for USA non residents. Lot of us, as USA non residents, have got gross amount of dividends from different USA (MLP) companies. This is confusing regarding that USA withholding tax deduction on dividends for USA non residents is usually 15%. Is it possible that we do not have to pay any taxes in USA on dividends from USA MLP and that all tax on dividends we have to report and pay only in our country of living?