May 17 (Reuters) - A former Japanese gangster shot his son, his daughter and two police officers on Thursday, and was holed up in his house with a female hostage, keeping police at bay.

It is the latest shoot-out to rattle tranquil Japan, where gun controls are tough and shootings are rare.

About a month ago, a gangster shot a fellow mobster and hid in an apartment before shooting himself in the head, and another gangster fatally shot the mayor of Nagasaki city.

Here are some facts about shootings, gang membership and cases of violent attacks against politicians in Japan.

- The number of shootings in Japan fell to a record low of 53 in 2006. Shooting incidents hit a peak of 200 in 2001.

- The number of murders in Japan totalled 589 in 2005, up 8 percent from a year earlier. In contrast, the United States had 16,692 cases of murder and non-negligent manslaughter in 2005, up 3 percent from 2004. The U.S. population is about 2.3 times that of Japan.

- Confiscated guns in Japan numbered 458 last year, down 6 percent from the year before.

- Of the total number of shootings in 2006, "yakuza" gangster groups were suspected in 36.

- Official membership in yakuza groups numbered 41,500 in 2006, down slightly from 2005, but the number of hangers-on rose marginally to 43,200.

- While violent attacks against politicians are infrequent, there have been several cases in recent years involving right-wing and yakuza groups, whose activities often overlap.

- The house of the mother of ruling Liberal Democratic Party lawmaker Koichi Kato was set on fire by a right-wing group member in August 2006 after Kato criticised then-Prime Minister Junichiro Koizumi's visit to a controversial war shrine.

- The last known murder of a politician was in October 2002, when lower house member Koki Ishii was stabbed to death by a member of a right-wing group in front of his Tokyo home.

- In May 1994, former prime minister Morihiro Hosokawa was threatened by gunfire by a former right-wing group member in a hotel in Tokyo, but he sustained no injuries. (Sources: National Police Agency, U.S. FBI, Reuters)

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