BERLIN/LONDON (Reuters) - Greece's shipping sector faces paying a higher tonnage tax, and a phase-out of the special tax allowances it has enjoyed, under the latest proposals presented by the country's creditors, according to documents seen by Reuters. Together with tourism, the shipping sector is a vital generator of income for Greece. According to an official document indicating steps Greece must take, its lenders say the country must "increase the rate of the tonnage tax and phase out special tax treatments of the shipping industry".