Question: What is the population rank of the socialist nation founded on the twentieth of September in 2015 ?

text: List of socialist states
Current socialist states -- Non-Marxist–Leninist states

Several past and present states have declared themselves socialist states or in the process of building socialism. The majority of self-declared socialist countries have been Marxist-Leninist or inspired by it, following the model of the Soviet Union or some form of people's or national democracy. They share a common definition of socialism and they refer to themselves as socialist states on the road to communism with a leading vanguard party structure, hence they are called communist states. Meanwhile, the countries in the non-Marxist-Leninist category represent a wide variety of different interpretations of the term socialism and in many cases the countries do not define what they mean by it. Modern uses of the term socialism are wide in meaning and interpretation. As a sovereign state is a different entity from the political party that rules that state at any given time, a country may be ruled by a socialist party without the country itself claiming to be socialist, occurring in both one-party and multi-party political systems. In particular, there are numerous cases of social democratic and democratic socialist parties winning elections in liberal democratic states and ruling for a number of terms until a different party wins the elections. While socialist parties won many elections around the world and most elections in the Nordic countries, they did not adopt socialism as the state ideology. Several countries with liberal democratic constitutions mention socialism. India is a liberal democracy that has been ruled by non-socialist parties on many occasions, but its constitution makes references to socialism. Certain other countries such as Croatia, Hungary, Myanmar and Poland have constitutions that make references to their communist and socialist past by recognizing or condemning it, but without claiming to be socialist in the present.
Country Since Duration Form of government Constitutional statement
People 's Republic of Bangladesh 11 April 1971 48 years , 301 days Multi-party parliamentary republic Preamble : Further pledging that it shall be a fundamental aim of the State to realise through the democratic process , a socialist society free from exploitation , a society in which the rule of law , fundamental human rights and freedoms , equality and justice , political , economic and social , will be secured for all citizens
Co-operative Republic of Guyana 6 October 1980 39 years , 123 days Multi-party presidential republic Section 1 , Article 1 : Guyana is an indivisible , secular , democratic sovereign state in the course of transition from capitalism to socialism and shall be known as the Co-operative Republic of Guyana
Republic of India 18 December 1976 43 years , 50 days Multi-party parliamentary republic Preamble : We , the people of India , having solemnly resolved to constitute India into a Sovereign Socialist Secular Democratic Republic and to secure to all its citizens
Democratic People 's Republic of Korea 19 February 1992 27 years , 352 days One-party socialist republic Preamble : The Democratic People 's Republic of Korea is the socialist motherland of Juche , which has applied the ideas and leadership of Kim Il-sung . Formerly a Marxist-Leninist state
Federal Democratic Republic of Nepal 20 September 2015 4 years , 139 days Multi-party parliamentary republic Section 1 , Article 4 : Nepal is an independent , indivisible , sovereign , secular , inclusive democratic , socialism-oriented federal democratic republican state
Republic of Nicaragua 1 January 1987 33 years , 36 days Dominant-party presidential republic Section 1 , Article 5 : Liberty , justice , respect for the dignity of the human person , political and social pluralism , the recognition of the distinct identity of the indigenous peoples and those of African descent within the framework of a unitary and indivisible state , the recognition of different forms of property , free international cooperation and respect for the free self-determination of peoples , Christian values , socialist ideals , and practices based on solidarity , and the values and ideals of the Nicaraguan culture and identity , are the principles of the Nicaraguan nation . [ ... ] The socialist ideals promote the common good over individual egoism , seeking to create an ever more inclusive , just and fair society , promoting an economic democracy which redistributes national wealth and eliminates exploitation among human beings
Portuguese Republic 2 April 1976 43 years , 310 days Multi-party semi-presidential republic Preamble : The Constituent Assembly affirms the Portuguese people 's decision to [ ... ] open up a path towards a socialist society
Democratic Socialist Republic of Sri Lanka 7 September 1978 41 years , 152 days Multi-party semi-presidential republic Preamble : [ ... ] to constitute Sri Lanka into a democratic socialist republic whilst ratifying the immutable republican principles of representative democracy , and assuring to all peoples freedom , equality , justice , fundamental human rights and the independence of the judiciary
United Republic of Tanzania 26 April 1964 55 years , 286 days Dominant-party semi-presidential republic Section 1 , Article 3 : The United Republic is a democratic , secular and socialist state which adheres to multi-party democracy