Formerly 40 points used to be the benchmark for safety from relegation, but this years Premier league table is very strange. The bottom 11 teams have 41 points and below. It becomes more dicey if Wigan eke out a win over Arsenal, then the battle for relegation will be fought out till the last day (May 19)
See how the bottom 11 teams look like

1 Man Utd. 88 37
2 Man City FC 75 36
3 Chelsea FC 72 37
4 Tottenham 69 37
5 Arsenal 67 36
6 Everton 63 37
7 Liverpool 58 37
8 West Brom Albn 48 37
9 Swansea 46 37
10 West Ham 43 37
11 Stoke 41 37
12 Norwich City 41 37
13 Newcastle 41 37
14 Southampton 40 37
15 Fulham 40 37
16 Aston Villa 40 37
17 Sunderland 39 37
18 Wigan Athletic 35 36
19 Reading 28 36
20 QPR 25 37