Iran's lead and zinc productions surpassed 50,000 tons in the first quarter of Iranian calendar year (started on March 20), showing over 13 percent rise comparing to the similar period last year. The amount totaled 52,800 tons with 13.7 percent increase comparing to the same period in 2012. Iran's lead and zinc products hit 13,400 tons late June and early July, while the amount surpassed 13,500 tons in the same amount last year. Iran is one of the most important mineral producers in the world, ranked among 15 major mineral-rich countries, holding some 68 types of minerals, 37 billion tons of proven reserves and more than 57 billion tons of potential reserves. Mineral production contributes only 0.6 per cent to the country’s GDP. The most important mines in Iran include coal, metallic minerals, sand and gravel, chemical minerals and salt. Khorasan has the most operating mines in Iran. Other large deposits are zinc (world's largest), copper (world's ninth largest - revised from second largest in 2010), iron (world's ninth largest), uranium (world's tenth largest) and lead (world's eleventh largest). Iran with roughly 1% of the world's population holds more than 7% of the world's total mineral reserves.