List of world number one snooker players

Columns: No | Nationality | Player | From | To
8 | Australia | Neil Robertson | 27 September 2010 | 12 December 2010 | Scotland | John Higgins ( 4 ) | 13 December 2010 | 2 May 2011 | Wales | Mark Williams ( 3 ) | 3 May 2011 | 11 September 2011 | 9 | England | Mark Selby | 12 September 2011 | 4 November 2012 | 10 | England | Judd Trump | 5 November 2012 | 9 December 2012 | England | Mark Selby ( 2 ) | 10 December 2012 | 17 February 2013

Example questions:
How many times was the person who became the top ranked snooker player in the world in 1983 a world champion ? | What does the British Broadcasting Company currently employ the person who became the top ranked snooker player in the world in 1990 as ? | How many career century breaks have been accumulated by the person who became the top ranked snooker player in the world in 2003 ? | How much has the person who became the top ranked snooker player in the world in 2002 earned from snooker tournaments ?

Answers:
six | commentator | 470 | £11 million