lead administration, who in turn represent the Thromde in the Dzongkhag Tshogdu. Likewise, geog elect headmen called gups, vice-headmen called mangmis, who also sit on the Dzongkhag Tshogdu, as well as other members of the Gewog Tshogde. The basis of electoral constituencies in Bhutan is the chiwog, a subdivision of gewogs delineated by the Election Commission. Economy Bhutan's currency is the ngultrum, whose value is fixed to the Indian rupee. The Indian rupee is also accepted as legal tender in the country. Though Bhutan's economy is one of the world's smallest, it has grown rapidly in recent years, by eight percent in 2005 and 14 percent in 2006. In 2007, Bhutan had the second-fastest-growing economy in the world, with an annual economic growth rate of 22.4 percent. This was mainly due to the commissioning of the gigantic Tala Hydroelectric Power Station. , Bhutan's per capita income was US$2,420. Bhutan's economy is based on agriculture, forestry, tourism and the sale of hydroelectric power to India. Agriculture provides the main livelihood for 55.4 percent of the population. Agrarian practices consist largely of subsistence farming and animal husbandry. Handicrafts, particularly weaving and the manufacture of religious art for home altars, are a small cottage industry. A landscape that varies from hilly to ruggedly mountainous has made the building of roads and other infrastructure difficult and expensive. This, and a lack of access to the sea, has meant that Bhutan has not been able to benefit from significant trading of its produce. Bhutan has no railways, though Indian Railways plans to link southern Bhutan to its vast network under an agreement signed in January 2005. Bhutan and India signed a 'free trade' accord in 2008, which additionally allowed Bhutanese imports and exports from third markets to transit India without tariffs. Bhutan had trade relations with the Tibet Autonomous Region of China until 1960, when it closed its border with China after an influx of refugees. Access to biocapacity in Bhutan is much higher than world average. In 2016, Bhutan had 5.0 global hectares of biocapacity per person within its territory, much more than the world average of 1.6 global hectares per person. In 2016 Bhutan used 4.5 global hectares of biocapacity per person—their ecological footprint of consumption. This means they use less biocapacity than Bhutan contains. As a result, Bhutan is running a biocapacity reserve. The industrial sector is currently in a nascent stage.