After Rav Yaakov Yosef recently paskened that people should not participate in the upcoming census due to issues of counting people, the census people got nervous that many would not take part in the census.

They then went to Rav Ovadia Yosef and Rav Elyashiv, and others to get their opinions on the matter. .
Ravs Elyashiv, Karelitz and Wosner paskened that it is ok to participate in the census. The reasoning is that the count includes non-Jews as well, along with the fact that the purpose is not just to know a number (i.e. how many Jews are there), but to plan infrastructures, such as building hospitals and the like. It is more of a "survey" than a "census", and therefore it is acceptable.

An interesting point mentioned in the Ynet article on the topic is that the census people agreed to the Rabbonim that they would not share the info with government offices such as the tax authority, so as not to harm people who do not report their income... very strange request for the rabbis to make, IMO...

The Mishpacha newspaper article that discussed the topic also mentioned that part of the reason for it being allowed is because they only "count" about 20% of the population, so it is not really a count anyway. Also, it is all an evaluation and not an accurate count.

So when the census people come calling, feel free to participate!