Over the longer term, Moldova's economy remains vulnerable to political uncertainty, weak administrative capacity, vested bureaucratic interests, corruption, higher fuel prices, Russian pressure, and the separatist regime in Moldova's Transnistria region. According to IMF World Economic Outlook April 2014, the Moldovan GDP (PPP) per capita is 3,927 International Dollars, excluding grey economy and tax evasion. With few natural energy resources, Moldova imports almost all of its energy supplies from Russia and Ukraine. Moldova's dependence on Russian energy is underscored by a growing US$5 billion debt to Russian natural gas supplier Gazprom, largely the result of unreimbursed natural gas consumption in the separatist Transnistria region. In August 2013, work began on a new pipeline between Moldova and Romania that may eventually break Russia's monopoly on Moldova's gas supplies. Moldova is a partner country of the EU INOGATE energy programme, which has four key topics: enhancing energy security, convergence of member state energy markets on the basis of EU internal energy market principles, supporting sustainable energy development, and attracting investment for energy projects of common and regional interest. The country has a well-established wine industry. It has a vineyard area of , of which are used for commercial production. Most of the country's wine production is made for export. Many families have their own recipes and grape varieties that have been passed down through the generations. Mileștii Mici is the home of the largest wine cellar in the world. It stretches for 200 km and holds almost 2 million bottles of wine  Moldova's rich soil and temperate continental climate (with warm summers and mild winters) have made the country one of the most productive agricultural regions since ancient times, and a major supplier of agricultural products in southeastern Europe. In agriculture, the economic reform started with the land cadastre reform. Moldova's agricultural products include vegetables, fruits, grapes, wine, and grains. The main means of transportation in Moldova are railways and a highway system ( overall, including of paved surfaces). The sole international air gateway of Moldova is the Chișinău International Airport. The Giurgiulești terminal on the Danube is compatible with small seagoing vessels. Shipping on the lower Prut and Nistru rivers plays only a modest role in the country's transportation system. The first million mobile telephone users were registered in September 2005. The number of mobile telephone users in Moldova increased by 47.3% in the first quarter of 2008 against the last year and exceeded 2.89 million.