Question: For the category with the lowest ranking , what is the measurement to categorize it by the source ?

text: International rankings of Iran
General
See also : Iran and Geography of Iran
The following are international rankings for Iran: §
Name Rank Out of Source Notes Year
Total area 18 233 United Nations Area of 1,628,750 km ; or ~1.1% of World 's total area 2010
Deadliest earthquakes in history 8 World List of natural disasters by death toll 856 Damghan earthquake killed more than 200,000 people in Iran on December 22 , 856 856
Countries by number of casualties from earthquakes 2 World United Nations Iran has the world 's second highest number of casualties due to earthquakes per one million residents . More info : The natural disasters risk index 2010
Number of major earthquakes 1 World United Nations Iran has the world 's highest number of major earthquakes . Tremors occur daily somewhere in the country . More info : online earthquake monitoring ( with GMT date & time stamp ) 2010
Number of billionaires N/A N/A List of Iranian people by net worth Iran has an estimated 3 million high net worth individuals , 32,000 individuals with a net worth of $ 3 million , 1,300 multimillionaires with net assets of $ 10 million or more and four billionaires ( living in Iran ) . See also : Social class in Iran and List of high net worth Iranians abroad 2016
World Giving Index 86 World Charities Aid Foundation Iran ranked 86th charitable nation worldwide with 35% of population having given money to charities , 38% of population having helped a stranger and only 12% having volunteered time . More info : World 's most charitable nations 2010
Intensity of natural background radiation 1 World Natural background radiation at Ramsar Highest natural radioactivity level in the world . Annual dose of 260 mSv . More info : Acute radiation syndrome and Ionizing radiation 2010
% of water area 102 139 List of countries by percentage of water area 12,000 km of sovereign water area or ~0.73% of total sovereign area 2010
Length of coastline 50 196 List of countries by length of coastline 2,440 km of total coastline length , excluding 740 km of coastline with the Caspian Sea , which is landlocked 2010
Land Area 18 World List of countries and outlying territories by land area 1,636,000 km of land area 2010
World 's largest islands 272 World List of islands by area Qeshm with an area of 1,336 km is the world 's 272nd largest island ( Greenland is the largest ) . More info : List of islands by highest point 2010
World 's highest points by country 22 World List of countries by highest point Damavand with a height of 5,610 m ( 18,406 ft ) . Damavand is also one of the Volcanic Seven Summits . More info : List of mountains in Iran and Extreme points of Earth 2010
World 's lowest points 17 World List of countries by lowest point Caspian Sea with a depth of 28 m below sea level is the world 's 17th deepest natural point 2010
World 's largest deserts 23 World List of deserts by area Dasht-e Kavir is the 23rd and Dasht-e Lut is the 25th largest desert in the world 2010
Most livable green countries 83 141 Reader 's Digest Composite measure of HDI and ESI 2008
Tea consumption per capita 5 World World Market Research Annual per capita tea consumption of 1.2 kg 2004
Coffee consumption per capita 132 World World Resources Institute Annual per capita coffee consumption of 0.1 kg 2006
Wheat consumption per capita 7 World US government Yearly consumption of ~195 kg per person 2004
Southernmost point by country 127 World List of countries by southernmost point South east of Sistan va Baluchestan at 25°03'35N 2010
Northernmost point by country 60 World List of countries by northernmost point West Azarbaijan region at 39°46'38N 2010