Input: Article: Barcelona is the only European club to have played continental football every season since 1955, and one of three clubs to have never been relegated from La Liga, along with Athletic Bilbao and Real Madrid. In 2009, Barcelona became the first club in Spain to win the treble consisting of La Liga, Copa del Rey, and the Champions League. That same year, it also became the first football club ever to win six out of six competitions in a single year, thus completing the sextuple, comprising the aforementioned treble and the Spanish Super Cup, UEFA Super Cup and FIFA Club World Cup. In the 2014–15 season, Barcelona won another historic treble, making them the first club in European football to win the treble twice.

Now answer this question: During which football season did Barcelona win its second treble?

Output: 2014–15

Input: Article: Service trials demonstrated another problem however: that ranging and tracking the new high-speed targets was almost impossible. At short range, the apparent target area is relatively large, the trajectory is flat and the time of flight is short, allowing to correct lead by watching the tracers. At long range, the aircraft remains in firing range for a long time, so the necessary calculations can in theory be done by slide rules - though, because small errors in distance cause large errors in shell fall height and detonation time, exact ranging is crucial. For the ranges and speeds that the Bofors worked at, neither answer was good enough.

Now answer this question: How was target lead watched at short range?

Output: by watching the tracers

Input: Article: Increasing state control over the oil sector, the RCC began a program of nationalization, starting with the expropriation of British Petroleum's share of the British Petroleum-N.B. Hunt Sahir Field in December 1971. In September 1973, it was announced that all foreign oil producers active in Libya were to be nationalized. For Gaddafi, this was an important step towards socialism. It proved an economic success; while gross domestic product had been $3.8 billion in 1969, it had risen to $13.7 billion in 1974, and $24.5 billion in 1979. In turn, the Libyans' standard of life greatly improved over the first decade of Gaddafi's administration, and by 1979 the average per-capita income was at $8,170, up from $40 in 1951; this was above the average of many industrialized countries like Italy and the U.K.

Now answer this question: What was Libya's per-capita income in 1951?

Output:
$40