To expand a little on chscag's answer, all batteries degrade over time. Yours (assuming it is the original battery) is three years old, I would say you are right at normal degradation with 89 percent of capacity (my 2009 MBP's battery is one month younger than yours, has 160 cycles and is at the same capacity).
As chscag noted, however, that battery will eventually decline until it is no longer giving you much battery life. This may take a while -- I had my BlackBook battery for five years and up into the fourth year it was still giving me four hours of light use on a charge, then it quickly deteriorated to about one reliable hour just before it's fifth birthday. My new(er) MBP's battery is easily good for five hours of normal use (for me, that means a LOT of surfing and internet stuff) and more if I dim the screen, turn off Bluetooth and Wi-Fi (say for watching a movie) or take other energy-saving measures.
You may not need a new battery for a long time yet, but when you do you'll know it thanks to Coconut Battery as I see you are using. A replacement one that *isn't a fire hazard* (ie cheap knockoff) will run you around $100 depending where you buy it.