Dallas Mavericks

31 seasons, 17 playoff seasons, 1 NBA Championship

Best season: 67-15
Worst season: 11-71
2010-11:

57-25

 NBA Champions
2009-10:

55-27

 Playoffs, first round
2008-09:

50-32

 Playoffs, second round
2007-08: 51-31 Playoffs, first round
2006-07: 67-15 Playoffs, first round
2005-06: 60-22 Playoffs, NBA Finals
2004-05: 58-24 Playoffs, second round
2003-04: 52-30 Playoffs, first round
2002-03: 60-22 Playoffs, Western Finals
2001-02: 57-25 Playoffs, second round
2000-01: 53-29 Playoffs, second round
1999-00: 40-42  
1998-99: 19-31  
1997-98: 20-62  
1996-97: 24-58  
1995-96: 26-56  
1994-95: 36-46  
1993-94: 13-69  
1992-93: 11-71  
1991-92: 22-60  
1990-91: 28-54  
1989-90: 47-35 Playoffs, first round
1988-89: 38-44  
1987-88: 53-29 Playoffs, Western Finals
1986-87: 55-27 Playoffs, first round
1985-86: 44-38 Playoffs, second round
1984-85: 44-38 Playoffs, first round
1983-84: 43-39 Playoffs, second round
1982-83: 38-44  
1981-82: 28-54  
1980-81: 15-67