World wine output may fall 5.3 percent this year because of excess rain that spoiled grape harvests in South America and adverse weather in French vineyards, resulting in one of the smallest vintages of the past 20 years, according to an intergovernmental group. Wine volume may fall to 259.5 million hectoliters from 273.9 million hectoliters last year, according to estimates from the International Organisation of Vine & Wine, a Paris-based group known by its French acronym OIV. Estimated output is equivalent…