Question: How long was Gustav Heinemann officially the President of the Federal Republic of Germany?

Context paragraphs:
German Finance Agency: The Federal Republic of Germany - Finance Agency (German: "Bundesrepublik Deutschland - Finanzagentur GmbH" ) is the central service provider for the Federal Republic of Germany's borrowing and debt management.  Thus it is wholly owned by the Federal Republic of Germany, represented by the Federal Ministry of Finance.  Legal basis is the Federal Government Debt Management Act (Bundesschuldenwesengesetz) that constitutes a special public control and supervision by the Federal Ministry of Finance which in addition itself regularly reports on debt management issues to budget experts from the German Bundestag.

Gerhard Schröder (CDU): Gerhard Schröder (11 September 1910 – 31 December 1989) was a West German politician and member of the Christian Democratic Union (CDU) party.  He served as Federal Minister of the Interior from 1953 to 1961, as Foreign Minister from 1961 to 1966, and as Minister of Defence from 1966 until 1969.  In the 1969 election he ran for President of Germany but was outpolled by Gustav Heinemann.

Gustav Heinemann Bridge: Gustav Heinemann Bridge (German: Gustav-Heinemann-Brücke) is a bridge connecting Berlin-Moabit and Tiergarten in Berlin, Germany.

West Germany: West Germany is the common English name for the Federal Republic of Germany or FRG (German: "Bundesrepublik Deutschland" ) in the period between its creation on 23 May 1949 and German reunification on 3 October 1990.  During this Cold War era, NATO-aligned West Germany and Warsaw Pact-aligned East Germany were divided by the Inner German border.  After 1961 West Berlin was physically separated from East Berlin as well as from East Germany by the Berlin Wall.  This situation ended when East Germany was dissolved and split into five states, which then joined the ten states of the Federal Republic of Germany along with the reunified city-state of Berlin.  With the reunification of West and East Germany, the Federal Republic of Germany, enlarged now to sixteen states, became known simply as "Germany".  This period is referred to as the Bonn Republic ("Bonner Republik") by historians, alluding to the interwar Weimar Republic and the post-reunification Berlin Republic.

Order of Merit of the Federal Republic of Germany: The Order of Merit of the Federal Republic of Germany ("Verdienstorden der Bundesrepublik Deutschland" ) is the only federal decoration of Germany.  It was created by the first President of the Federal Republic of Germany, Theodor Heuss, on 7 September 1951, and has been awarded to over 200,000 individuals in total, both Germans and foreigners.  Since the 1990s the number of annual awards has declined from over 4,000, first to around 2,300—2,500 per year, and now under 2,000, with a low of 1752 in 2011.  In recent years women have made up a steady 30—31% of recipients.  Colloquially, the decorations of the different classes of the Order are also known as the Federal Cross of Merit (German: "Bundesverdienstkreuz" ).

Diether Posser: During his childhood in Essen he was influenced by the Lutheran church.  After serving in the military for the required time Posser studied law and became a lawyer in 1951.  In 1952 he founded, with the former Secretary of the Interior Gustav Heinemann (previously of the CDU), Hans Bodensteiner (from the CSU), Thea Arnold, Helene Wessel (both from the Zentrumspartei), Hermann Etzel (Bayernpartei), and the future President Johannes Rau the pacifist All-German People's Party, of which he was made General Secretary after the 1953 resignation of Bodensteiner.

West German presidential election, 1974: An indirect presidential election (officially the 6th Federal Convention) was held in West Germany on 23 May 1974.  Though not term limited, incumbent Gustav Heinemann chose not to seek a second term.  The government parties (SPD and FDP) nominated Vice-Chancellor Walter Scheel; the Christian Democratic Union nominated Richard von Weizsäcker.  Scheel won the election by 32 votes on the first ballot.  He served as president until 1979.  Weizsäcker would later serve as president from 1984 to 1994.

Gustav Heinemann: Gustav Walter Heinemann (23 July 1899 – 7 July 1976) was a German politician.  He was Mayor of the city of Essen from 1946 to 1949, West German Minister of the Interior from 1949 to 1950, Minister of Justice from 1966 to 1969 and President of the Federal Republic of Germany (West Germany) from 1969 to 1974.

President of Germany: The President of Germany, officially the President of the Federal Republic of Germany (German: "Bundespräsident der Bundesrepublik Deutschland" ), is the head of state of Germany.

West German presidential election, 1969: An indirect presidential election (officially the 5th Federal Convention) was held in West Germany on 5 March 1969.  The incumbent President, Heinrich Lübke had served two terms and was therefore ineligible for a third.  The Christian Democratic Union nominated defense minister Gerhard Schröder.  Schröder was a controversial choice, even within his own party, since he had been a member of the NSDAP and the SA under Hitler.  Other potential candidates included Helmut Kohl and Richard von Weizsäcker, relatively unknown names at the time, who would go on to serve as Chancellor and President respectively.  Justice Minister Gustav Heinemann was nominated by the Social Democratic Party and supported by the opposition Free Democratic Party.  With neither candidate able to win an absolute majority, Heinemann won the election on the third ballot by only 6 votes.

Supporting paragraphs: Gustav Heinemann President of Germany
Answer: from 1969 to 1974.