CREATE TABLE "singles_performance_timeline" (
  "tournament" text,
  "2000" text,
  "1999" text,
  "1998" text,
  "1997" text,
  "1996" text,
  "1995" text,
  "1994" text,
  "1993" text,
  "1992" text,
  "1991" text
);

Question: What is the 1994 when QF is 1999?
SQL: SELECT "1994" FROM "singles_performance_timeline" WHERE "1999"='qf';

Question: What is the 1991 when 1997 is 18?
SQL: SELECT "1991" FROM "singles_performance_timeline" WHERE "1997"='18';

Question: What's the 1991 when 1999 is 14?
SQL: SELECT "1991" FROM "singles_performance_timeline" WHERE "1999"='14';

Question: What's the 1996 when 1997 is 3R?
SQL: SELECT "1996" FROM "singles_performance_timeline" WHERE "1997"='3r';

Question: What is 1994 when 1996 is 3R?
SQL: SELECT "1994" FROM "singles_performance_timeline" WHERE "1996"='3r';

Question: What is 1996 during the US Open?
SQL: SELECT "1996" FROM "singles_performance_timeline" WHERE "tournament"='us open';