The number of pensioners has doubled in the 60 years since the Queen took the throne and 44 times as many people reach age 100.
Figures from the Department for Work and Pensions also showed people, on average, are living nearly a decade longer.
There are 5.6 million more pensioners today than in 1952, rising from 6.8 million to 12.4 million.
And there are about 13,120 more centenarians, an increase on 300 in 1952. The Queen has sent about 110,000 telegrams and messages to centenarians during her reign.
Pensions minister Steve Webb said: "In the past 60 years we have seen man land on the moon, the fall of the Berlin Wall and the rise of the Internet and digital technology. Pensioners now make up 20% of the population and make a huge contribution to society."
However, Webb said the state pension age had not kept up with the changes and the current pension has trapped millions of people in "means-testing maw" for decades.
The government is set to bring forward the state pension age to 67 by 2028 and create a single-tier pension, estimated to be about £140 per week.
The DWP said a boy born in 1952 was expected to live to 78 and a girl to 83. A boy born in 2012 is expected to live to 91 and a girl to 94.
And while the Queen and the Duke of Edinburgh continue their busy schedule of Royal engagements, very few people are reported as employed at aged 86 or over.
About 350,000 women aged 65 or over are in work today and some 540,000 men aged 65 or over.
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