A 90-fold increase since 1911 in the number of people aged 100 or over is a significant factor in planning health-service provision, new figures suggest.
The Office for National Statistics (ONS) says that major factors behind the increase are improved medical treatment, hygiene and sanitation and better housing, living standards and nutrition.
In 1911, there were just 100 centenarians, but in 2007 there were 9,300 – and the increase has not been constant.
Before 1940, the average annual increase was 1.9%, but over the next 40 years it was 6.4%, with numbers reaching over 1,000 by the end of the 1960s.
Annual growth rates slowed between 1981 and 2001, reflecting in part a reduction in the pace of births increase a century earlier. These cohorts will also have been affected by deaths caused by the First World War and the 1918/19 flu pandemic.
Mortality rates are expected to continue to improve over the 21st century, leading to more old people who may put increasing pressure on health-service provision.
ONS said that there are more women centenarians – seven women for every man in mid-2007 – but the ratio is beginning to fall as recent mortality improvements have been greater for men.