Any suggestion on how to treat Xbee RSSIdur?

I have an Xbee configured as receiver and Arduino (standalone w/ atmega328p chip) connected together. The RSSI pin of the Xbee is connected to one of the Arduino Board PWM pin. I used the PulseIn to get the digital equivalent of the RSSI (i named it rssiDur) I used the Hyperterminal to display the rssiDur value. The rssiDur values displayed on the HT is not consistent. Any interference between my Xbees changes the rssiDur dramatically. I wish to stabilize the rssiDur reading so that the interference will not be of great effect.

It has been suggested to use a timer. I don't know how though. It was something like when the rssiDur displays 10 consecutive of the same value, that value will be the rssiDur. ( example: 9 9 9 9 9 9 9 9 9 9 8 8 6 7 10, rssiDur=9) Does anyone know how to do this? Or any suggestions on how to treat the values of rssiDur? it will much help on our project. Thank you.