COUNTRIES making up over 60% of the world's economic output and more than half of its population hold elections this year. Markets face a "ballot box bombshell", financial services group Morningstar says, adding: "Prior experience of this kind of event risk shows big changes can cause sell-offs". Here's a look at the elections that matter for markets, in roughly chronological order for the coming year. 1/ TAIWAN Date: Jan 13 Back story: Taiwan's ruling Democratic Progressive Party (DPP) is competing mainly with the opposition Kuomintang (KMT) for the presidency and legislature. A DPP win would be the third consecutive victory for a…