The UK arm of US grocery chain Whole Foods Market has cut its annual pre-tax loss by almost half as its sales increased by a quarter last year.

Newly filed accounts at Companies House reveal the health-focussed supermarket recorded sales of £101.4m in the year to 28 September 2014 – a rise of 24.3% year-on-year.

The sales boost was driven by a 6.8% rise in sales from existing stores and the opening of two high profile new stores in Fulham Broadway and Richmond during the financial year. The 24.3% growth was slightly below the 28.6% top-line revenue growth achieved during the previous year.

Total administrative expenses were slashed by almost 10 percentage points as a proportion of sales, coming in at £48.4m (47.8% of total sales). As a result, the chain cut its pre-tax loss from £14.2m to £7.5m last year.

The upmarket chain has yet to record a profit in the UK after 15 years’ trading, initially as Fresh and Wild before Whole Foods bought up the UK chain in 2004. However, last year’s loss was the smallest recorded since the £4.4m loss posted in the year to September 2011.

Writing in the accounts, the chain said the profitability improvement reflected “operational efficiencies gained by the stores teams driven by strong shrink reduction”.

The firm also benefited from taking a write-down on its property of £6.4m in the 2013 financial year, while no impairment charges were recorded last year.

Despite the focus on efficiency, the chain added 160 staff members during the year to support the opening of the two new London stores, bringing its total headcount up to 1,135. As a result wages rose by approximately 20% to £28.7m for the year.

As of September 28, the company operated nine stores in the UK under the Whole Foods Market brand. Whole Foods launched its first branded UK superstore in London’s Kensington in 2007.

Whole Foods Market said in the accounts: “We remain committed to supporting regional producers and this commitment is evident in the host of locally sourced products in our stores. It is our goal to be the finest food shop in every community we serve”.

Whole Foods has been recovering from a tough time in the US in recent months, with its shares climbing by around 55% since mid-October 2014.