Where Switzerland is young and where it is old

Where the oldest residents live

Share of people aged 65 and over is the simplest measure of an ageing community. The median municipality stands at 20.7%. At the top, Orselina reaches 42.7%, followed by Onsernone at 42.5% and Ronco sopra Ascona at 42.4%. The four highest shares are all found in the canton of Ticino. The pattern is not confined to that canton, though: Mont-Noble, in the canton of Valais, is ranked 5 of 1,811 with 36.8%.

The oldest age group is just as concentrated. Share of people aged 80 and over reaches 14.4% in Orselina, against a median of 5.6% across municipalities. Old age and small households go together: in Orselina the average household has 1.72 persons, the old-age dependency ratio stands at 84.6 per 100 people and young people make up only 6.9% of residents.

Large cities sit well below the median. Zürich has 14.3%, Lausanne has 14.5% and Geneva has 16.0%. Lugano stands higher, with 23.1%, which places it above the median of 20.7%.

Cities of young adults

Share of 20- to 39-year-olds tells the opposite story. The median municipality stands at 22.8%, but the top of the table belongs to cities and their suburbs: Chavannes-près-Renens has 44.4%, Crissier has 34.9% and Zürich has 34.9%.

Other big cities follow at a distance. Bern has 32.9%, St. Gallen has 32.4%, Lucerne has 31.8% and Basel has 30.4%. In Lugano the share is 24.8% and in Bellinzona it is 24.3%, much closer to the median than Zürich.

Young adults and older residents are mirror images. Zürich has 34.9% of young adults and 14.3% of older residents, while Orselina has 15.1% and 42.7%. Across the country the two shares move in opposite directions, so a place rich in one tends to be poor in the other.

Families and large households

Share of people under 20 has a geography of its own. The median municipality stands at 20.4%, and the highest values are concentrated in one canton: Chavannes-des-Bois has 30.5%, Bogis-Bossey has 29.3%, and all five highest are found in Vaud. The family-heavy municipalities are not only tiny villages: Ollon has 8,297 residents. Big cities have fewer young people than the median: Zürich has 17.7%, Basel has 17.2% and Bern has 17.2%.

Households follow a similar geography. The average household size peaks at 2.91 persons in Vandoeuvres, followed by Laconnex at 2.89 persons, and the three largest are found in Geneva. The median household has 2.26 persons. Large cities sit at the other end of the scale: 2.00 persons in Zürich, 1.92 persons in Basel and 1.96 persons in Bern.

Household size and age do not always move together. Lauterbrunnen has an average of 1.75 persons, close to the smallest households in the country, yet only 26.1% of its residents are older, compared with 42.7% in Orselina. Both measures describe the same municipality from different sides, and neither is a verdict on it.

Births, deaths and arrivals

Three flows shape the age structure over time: where natural change is positive and arrivals are many, a municipality stays young, and where both are weak it ages quickly. In the median municipality natural change, births minus deaths, is only 0.6 per 1,000 inhabitants, whereas net migration is 8.9 per 1,000 inhabitants. Arrivals matter far more than births in the typical case, and the median population change over ten years is +9.0%.

Chavannes-près-Renens shows the effect of arrivals. Its net migration is 60.2 per 1,000 inhabitants, its birth rate is 9.4 per 1,000 inhabitants, and its population has changed by +45.1% in ten years, ranked 6 of 1,811. With net migration of 55.2 per 1,000 inhabitants, Crissier has a similar profile. Cities with many young adults can still have more births than deaths: natural change of 3.1 per 1,000 inhabitants in Zürich, of 3.3 per 1,000 inhabitants in Lausanne, but of −0.5 per 1,000 inhabitants in Basel.

In Orselina deaths outnumber births: natural change is −10.6 per 1,000 inhabitants and net migration is only 1.4 per 1,000 inhabitants. Over ten years the population has changed by −10.1%. Brissago shows the same pattern, with natural change of −12.1 per 1,000 inhabitants and a ten-year change of −10.9%.

Small numbers swing quickly. In a very small municipality, a handful of births more or fewer moves the rate noticeably, which is why the national tables for shares leave out the smallest municipalities. Rates for villages are best read as indications.

Reading the age figures

Age shares describe the resident population. They leave out people who work in a municipality without living there, and visitors who stay in holiday homes registered elsewhere. A high share of young adults can reflect studies, first jobs or small flats, and the figures alone do not tell which.

The old-age dependency ratio puts older residents in relation to people of working age. It runs from 12.9 per 100 people in Chavannes-près-Renens to 85.8 per 100 people in Onsernone, with a median of 35.1 per 100 people.

Each share also depends on the others. When one age group is large, the rest must be smaller, which is why the shares of older residents, young adults and young people are best read together rather than one at a time.