UK self-storage giant Big Yellow Group reported a year-on-year decline in total store revenue for the first quarter, following a fall in average rental yield.Total store revenue for company's 54 stores came to £16.7m for the three months to end of June, up 5.0% from £15.9m the previous quarter but down 1.2% from £16.9m a year earlier. The year-on-year drop in revenue was in line with guidance and reflected a reduction in average rental yield following the introduction of VAT on self-storage sales from October 1st.The 54 stores achieved an average net rent per sq ft over the quarter of £25.18, up 0.2% from £25.14 for the quarter to March 31st and down 6.3% from £26.88 for the same quarter last year.It was offset in part by growth in occupancy. Wholly owned stores grew in occupancy by 134,000 sq ft, compared to 122,000 sq ft last year. Occupancy across 12 stores in Big Yellow Limited Partnership grew by 35,000 sq ft in the quarter to 444,000 sq ft, representing 59.3% of their 749,000 sq ft total total maximum lettable area (MLA) at the end of the quarter.This compares to 386,000 sq ft occupied (51.5% of MLA) at the same time last year and 409,000 (54.6% of MLA) sq ft occupied at March 31st 2013.Total store revenue for the 12 stores was £2.2m for the quarter, a 10% increase from the prior quarter's £2.0m and a 16% rise from the previous year's £1.9m.The net rent per sq ft of the 12 stores at June 30th was £17.24, an increase of 3.1% from £16.72 at March 31st. The stores achieved an average net rent per sq ft over the quarter of £17.25, up 1.5% from £17 for the three months to March 31st and 4.9% down from £18.14 for the same quarter last year.James Gibson, Chief Executive Officer, said: "This is a good start to the year with improving demand and we expect to deliver further occupancy gains over the summer."The performance for the year will depend on our historically weaker December quarter when we see a spike in short term vacates from domestic and student customers."Our focus remains on earnings and cash flow growth through increasing occupancy and revenue leveraging off our market leading brand and operating platform."The company has started the construction of a 70,000 sq ft store at Gypsy Corner, West London. The store will open in April 2014.RD