A bit much

Can someone explain how the summons to jury service system works?

I thought it was supposed to be random selection.

However, I have lived in Hong Kong for 15 years and every three years on the dot I have been called to serve.

Others I know who have lived here as long or longer have never been called.

I do not mind doing my civic duty as long as I am not doing someone else's as well.

NAME AND ADDRESS SUPPLIED