According to INE, during the first response phase of the Census 2021, which started on 19 April and ended on Monday, about 3.7 million responses were recorded, representing a total of more than 9 million registered persons.

"All regions present a high level of response, with the Autonomous Region of Madeira, with 90 percent, registering the highest value," INE said.

The response to the Census 2021 was mostly given through the Internet (eCensos), which recorded about 90 percent of total responses. The remaining 10 percent of responses were given via eBalcão, available in parish councils, by telephone or resulted from direct support by the census taker, it adds.

The institute also stresses that, over the last week, the number of daily responses varied between 100 and 200,000, with the highest figures being recorded on Sunday 2 May.

The pace of responses and the "excellent collaboration" received from the population allowed to anticipate a stage in the collection, says INE, informing that, from 4 May until the end of the month, households that have not yet responded will receive a contact notice or a visit from the census taker reminding them of the need to respond to the Census and provide all necessary support to the population.

The Internet continues to be the preferred mode of response for the 2021 Census, "particularly taking into account the public health situation", reminds the institute.

However, the population can still respond by telephone via the helpline (21 054 2021), by 'eBalcony' (in parish councils) and by self-completion of paper questionnaires, delivered by census takers.

INE asks that the response be given as soon as possible, ensuring greater proximity to the reference day of the Census 2021 (19 April) and avoiding contact by the census taker, "who may direct their efforts to support people with greater difficulty in answering,".

In cases of failure to receive a letter with response codes, the population should contact the helpline or wait for the visit of the census taker.

In all, around 15,000 people are involved in conducting and processing the Census 2021 data.