using 4,150,000 tons in 2013. At one point the price of the world's benchmark smoked rubber sheet dropped as low as US$1.27 per kilogram, or 80 percent below the record high of US$6.40 per kg in February 2011. Similarly, rubber futures in Shanghai have dropped by 22 percent and the export price of Thai rubber by 23 percent. Then, as prices began to rebound, the southern provinces of Thailand, where two-thirds of the Thai rubber plantations are located, were hit by torrential rains and flooding at the peak of the rubber-tapping season. The Rubber Authority of Thailand forecasts that output will drop 7.6 percent in 2017. Farmers, unable to harvest rubber sap due to high water, are unable to take advantage of the highest rubber prices in four years. Largely due to the flooding, prices for unsmoked USS3 rubber sheets in Nakhon Si Thammarat have increased steadily and reached 84.32 baht (US$2.38) per kilogram in January 2017 and will likely go higher. Rubber growers face an even greater danger: rubber trees die after 20 days when inundated by flood waters. Farmers face an on-going disaster in 2018: rubber production costs amount to 63 baht per kilogram, but rubber can be sold for only 40 baht per kilogram. At the industry high point in 2011, farmers earned 713 billion baht from rubber sales, now down 72 percent in 2018 to 274 billion baht. The number of households farming rubber trees has declined to 1.4 million in 2018, compared with 1.6 million in 2014, yet the area devoted to rubber plantations continues to rise, to 20.6 million rai in 2018, up from 19.5 million rai in 2016 and 12.9 million rai in 2007. Isan (northeastern Thailand), has 5.2 million rai of rubber trees. Most of them are concentrated in Bueng Kan Province on the Mekong River, with some 800,000 rai of rubber groves. The second and third largest rubber-growing areas in Isan are the provinces of Loei (700,000 rai) and Udon Thani (500,000 rai) of rubber farms. Farmers there were selling their raw product to processors for under 20 baht per kilogram as of October 2019. As recently as 2012, one kilogram sold for 80–90 baht. Many Isan farmers took up rubber cultivation as a result of the government's "Million Rai of Rubber Trees" program in 2004. The policy encouraged the expansion of rubber farms in the north and northeast and is