It needs to be more like 7.5%, or the economy will be a drag on Obama. That does not mean he won't win however. There are a lot of variables at play.
A sitting President has never in modern history won reelection at a time when the economy was considered to be bad. It looked as if Bush 41 might in the spring of 1992, but in the end the economy was too much for him to overcome, even though the recession had been over for more than a year.
A key indicator is consumer confidence. It has to be over 95 for a President to be reelected. Its currently around 50.
Here is the consumer confidence numbers for every October before reelection going back to 1972:
2004: 97
1996: 112
1992: 58
1984: 100
1976: 91
1972: 107
