At the start of trading on Thursday, the greenback gained a further 36 paisas and reached the historic Rs300 milestone in the interbank market also.In the open market, the US currency had crossed a triple century a few days ago already.In just two weeks, the dollar has gained a magnanimous Rs13 in the interbank market.On Wednesday, the US dollar had maintained its historic high rate in the Pakistani currency market. Wednesday’s trading session had opened with a further rise in the mighty currency.Currency dealers said the dollar returned after marking a triple century.