Municipality Trebnje, which is part of the Jugovzhodna Slovenia statistical region, measures 195 km2; this ranks it 28th among Slovene municipalities.
Statistical data for 2008 reveal the following:
At the end of 2008 about 14,400 people (about 7,400 men and 7,000 women) were living in the municipality, which ranks Trebnje 37th among Slovene municipalities. The population density was 74 people per square kilometre, which was lower than the national average of 100 people per square kilometre.
The number of live births was higher than the number of deaths, which means that natural increase per 1,000 population in the municipality was positive. It was 4.2 (in Slovenia 1.7). The number of people who moved from the municipality was lower than the number of people who moved into the municipality, so net migration per 1,000 population in the municipality was positive. It was 22.9. The sum of natural increase and net migration per 1,000 population in the municipality was positive. It was 27.0 (in Slovenia 10.9).
The mean age of people in Trebnje was 39.4 years, which was lower than the national average (41.3 years).
In contrast to most Slovene municipalities, in Trebnje the number of young people was higher than the number of old people: there were 95 people, aged 65 or more, per 100 people aged 0–14. This ratio shows that the value of the ageing index was lower than the national average of 118. It also shows that the mean age of people in Trebnje is growing more slowly than in Slovenia as a whole. Data by sex show that the ageing index for women was in all Slovene municipalities higher than the ageing index for men. In Trebnje – as in most Slovene municipalities – more women were 65+ years old than 14 or less; for men the situation was exactly the opposite.
Trebnje had 3 kindergartens. They were attended by 505 children. Of all children aged 1–5, 69% were included in kindergartens, which was less than the national average of 70%. In the school year 2008/09 elementary schools in Trebnje were attended by about 1,300 pupils. About 730 pupils from the municipality attended various secondary schools. There were 60 students and 9 graduates per 1,000 people in the municipality; in Slovenia the averages were 55 per 1,000 and 8 per 1,000, respectively.
Among people aged 15–64 (i.e. working age population) about 66% were persons in employment (i.e. persons in paid employment or self-employed persons), which is more than the national average of 62%.
The registered unemployment rate was 4.8%, which is less than the national average (6.7%). As in most Slovene municipalities, more women than men were unemployed.
In Trebnje, average monthly gross earnings per person employed by legal persons were about 7% lower than the annual average of monthly earnings for Slovenia; and net earnings about 5% lower.
Every 50th person in the municipality was receiving at least one financial social assistance. In Slovenia as a whole every 28th person received at least one financial social assistance.
The value of gross investment in new fixed assets in the municipality (EUR 6,156 per capita) was higher than the national average (EUR 3,165 EUR per capita).
In 2008, there were 443 dwellings per 1,000 population. About 53% of dwellings had at least three rooms. Average size of dwellings in the municipality was 78 m2.
About every other person in Trebnje had a car (63 passenger cars per 100 population); cars in this municipality were on average 8 years old.
In 2008, 535 kg of municipal waste per person was collected in Trebnje, which is 116 kg more than on average in Slovenia.