Aug 18 (Reuters) - Canada’s main stock index slipped for the fifth straight session on Wednesday, weighed down by materials sector, while data showed annual inflation rate climbed at its fastest pace since 2011. At 14:30 a.m. ET (13:30 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 47.02 points, or 0.23%, at 20,316.57. (Reporting by Sruthi Shankar in Bengaluru; Editing by Sriraj Kalluvila) Our Standards: The Thomson Reuters Trust Principles.