As of the 5th of March 2015, there have been two conclaves this century. The first was in 2005, which elected Pope Benedict XVI. The second was in 2013, which elected Pope Francis I.

That depends on how fast the cardinals can come to a consensus. Over the centuries conclaves have been as short as 10 hours and as long as nearly 3 years.

He was chosen as pope because the College of cardinals, under the guidance of the Holy Spirit, decided he was the best man for the job. Since conclaves are secret, we will probably know little else about the reasons he was chosen.

Paul VI limited particiaption in conclaves to those cardinals under the age of 80 at the start of the conclave. He also expanded the number of cardinal electors from 70 to 120.

Papal conclaves are secret so we will never know absolutely. However, Camillo Cardinal Laurenti participated in the 1922 papal conclave and it has been purported that he was elected as Pope, but according to The Compact History Of The Popes, "he refused to accept the honor". The voting then continued and Pope Pius XI was elected.