Computer codes for the TSP have become increasingly more sophisticated over the years.  A conspicuous sign of these improvements is the increasing size of nontrivial instances that have been solved, moving from Dantzig, Fulkerson, and Johnson's solution of a 49-city problem in 1954 up through the solution of a 24,978-city problem 50 years later.

Year Research Team Size of Instance Name
1954 G. Dantzig, R. Fulkerson, and S. Johnson 49 cities dantzig42
1971 M. Held and R.M. Karp 64 cities 64 random points
1975 P.M. Camerini, L. Fratta, and F. Maffioli 67 cities 67 random points
1977 M. Grötschel 120 cities gr120
1980 H. Crowder and M.W. Padberg 318 cities lin318
1987 M. Padberg and G. Rinaldi 532 cities att532
1987 M. Grötschel and O. Holland 666 cities gr666
1987 M. Padberg and G. Rinaldi 2,392 cities pr2392
1994 D. Applegate, R. Bixby, V. Chvátal, and W. Cook 7,397 cities pla7397
1998 D. Applegate, R. Bixby, V. Chvátal, and W. Cook 13,509 cities usa13509
2001 D. Applegate, R. Bixby, V. Chvátal, and W. Cook 15,112 cities d15112
2004 D. Applegate, R. Bixby, V. Chvátal, W. Cook,
and K. Helsgaun
24,978 cities sw24798