Roll and Pitch values are not stable

[isso11]

Hi guys,
I'm interfacing the mpu6050 with Tiva C arm cortex m4 basesd launchpad "TM4C123GH6PM"
I setup up the configuration of the IMU and when I ran I got a weird behavior from  PITCH and ROLL readings. The vales should always read zero when leveled up.. but after  every 4 or 5 outputs they go high.
 

 

    Roll : 82.890320    Pitch : 44.777519 

    Roll : 0.119266      Pitch : 82.930687 

    Roll : 0.070139      Pitch : 82.928864 

    Roll : 82.983780    Pitch : 44.805222 

    Roll : 0.049558      Pitch : 0.063718 

    Roll : 82.967545    Pitch : 0.014765 

    Roll : 82.964287    Pitch : 44.801392 

    Roll : 0.035360      Pitch : 82.988754 

    Roll : 0.035095      Pitch : 82.937157 

    Roll : 0.042208      Pitch : 82.950836 

    Roll : 0.161359      Pitch : 0.014031 

    Roll : 82.955894    Pitch : 0.002605 

    Roll : 0.021050      Pitch : 82.933815