List of world number one snooker players

Columns: No | Nationality | Player | From | To
1 | Wales | Ray Reardon | 3 May 1975 | 20 April 1981 | 2 | Canada | Cliff Thorburn | 21 April 1981 | 16 May 1982 | Wales | Ray Reardon ( 2 ) | 17 May 1982 | 2 May 1983 | 3 | England | Steve Davis | 3 May 1983 | 29 April 1990 | 4 | Scotland | Stephen Hendry | 30 April 1990 | 4 May 1998 | 5 | Scotland | John Higgins | 5 May 1998 | 1 May 2000 | 6 | Wales | Mark Williams | 2 May 2000 | 6 May 2002

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