The official exchange rate of the Belarusian ruble against the dollar continues to grow.It increased by 50 rubles to 11,850 Belarusian rubles a dollar on the Belarusian Stock and Currency Exchange, Nasha Niva reports.Yesterday's official rate of the Belarusian ruble rose by 770 rubles from 11,030 to 11,800 rubles a dollar.The ruble to euro exchange rate didn't change. It remains 14,380 rubles. The Russian ruble costs 214,5 Belarusian rubles.