The Japanese central bank is mulling over a cut in the estimation of real gross domestic product growth in 2011 after a survey revealed a fall in the country\'s business confidence among large companies on Friday, local media reported. The Bank of Japan is likely to lower its forecast of real gross domestic product growth to between 0.1 and 0.4 percent, from 0.6 percent projected in April, Kyodo News reported. Business confidence among Japan\'s largest manufacturers dropped sharply in the three months to June from the previous quarter, due to fallout from the March 11 earthquake and tsunami, the BOJ said in a report on Friday. The quarterly Tankan diffusion index of sentiment at large Japanese manufacturers fell to minus 9 in June, following a reading of plus 6 in March and 5 in December.