The Queen has published her annual public accounts revealing how taxpayers' money is spent by members of the Royal Family.
Last year the Royal Family cost taxpayers £37.4m
The documents show that the royals cost £37.3m last year - the equivalent of 62p per UK taxpayer - and 0.3% less than in 2005-6.
The figures include £1.1m on hospitality and £2.2m on helicopters.
Republic, the campaign for an elected head of state, said £37m was "fantasy" and claimed the real figure was £150m.
Campaign manager Graham Smith said the Royal Family had not included security costs or tax breaks in their calculation.
"This blatant spin would put Alastair Campbell to shame," said Mr Smith.
He added: "It is absurd that the royals still manage to spend tens of thousands of pounds on individual journeys within the UK.
"A first class rail ticket or even a private car would be a tiny fraction of the cost to the taxpayer and a lot better for the environment."
Sir Alan Reid, Keeper of the Privy Purse, said the public was getting "the best value for money in all areas".
In all, £5.6m was spent on travel, including £2.2m for 514 hours of helicopter use.
The Prince of Wales and the Duchess of Cornwall took the single most expensive trip.
Their tour of the Gulf states in February taking in Kuwait, Qatar, the United Arab Emirates and Bahrain cost £345,710.
A total of £8.8m was spent on salaries for Royal staff and £1.1m on hospitality and catering, including garden parties.
Sir Alan said the cost of the Royal Family had fallen by 2.7% in real terms from last year and 7% in since 2001.
"The reduction in the amount of head of state expenditure reflects the continuous attention the Royal household pays to obtaining the best value for money in all areas of expenditure," Sir Alan said.
But the BBC's royal correspondent, Nicholas Witchell, said the accounts also revealed major problems with the structure of Buckingham Palace.
The Prince of Wales and Duchess of Cornwall toured the Gulf states
There is, he said, a major health and safety risk involving crumbling brickwork and plaster which will cost £3m to rectify.
The bulk of the reduction in Royal costs was reportedly in the refurbishment of the palace of Holyroodhouse.
But Sir Alan warned there was a "critical backlog" in maintenance work on Royal buildings and said it was essential that the government gave an additional £1m a year to cover the costs.
Earlier this week, Prince Charles published figures showing that his household has gone carbon neutral.
He also cut his overall carbon emissions by 9% in the last year by taking fewer flights and switching to "green electricity" at Highgrove.
The Queen is now said to be following his lead and the Royal household has begun measuring its carbon footprint.
Sir Alan said: "Success has been achieved in reducing carbon emissions on gas and electricity by 1,000 tonnes or 12% during the year, through lower energy consumption and the introduction of a new combined heat and power plant at Windsor Castle."
One area of increase in this year's accounts was the cost of dealing with Freedom of Information requests.