I filled in the "how many in household" box and nothing more.
Some time later two people showed up and asked me if they could ask more questions, I explained I did my Constitutional duties and would provide nothing more. They understood and walked away.
No muss, no fuss.
And the Census continues, they send out a detailed questionnaire, a quarter of a million of them every month. I have been threatened with large fines and prison time by several callers. I asked to be sent those parts of the law that authorized what they are doing. The forth time I asked they finally sent that which authorizes the census every ten years. They apparently think I’m stupid. I no longer take their calls. The census bureau has called eight times in the last two days. If they show up on my property I will call the sheriff to report trespassers and greet them with shotgun in hand, if they don’t leave posthaste I will use said gun.
Actually we had multiple census workers in our backyard over the past 11 years. They continued to call and said I was paranoid for not providing all the requested information. Eventually I disconnected the phone they kept calling. Haven't seen any census workers in a couple of years.