battery show mutliple of 10 only

Suggest you try the BatteryLeft app. It will calibrate your battery discharge over time, and once calibration is completed, will give 1% incremental readings on the Notification Bar and on its own widget, along with other useful data.
 
Yeah, that's just the way it is.

Like vicw926a4 said, you can use applications that calibrate your battery and give you ESTIMATES of your battery percentage left in 1% increments but that's all for now.