Storage barn operator Big Yellow saw 'occupancy growth' up from 143,000 square feet in the second quarter of 2010 to 162,000 square feet between April and June this year.Big Yellow wholly owns 52 of its stores, and at these outlets annualised revenue was up 7% compared to the first half of 2010 at £63.7m. The 11 "partnership stores" were up 64% from June 2010 at £3.9m.The wholly owned stores are operating at 61.3% of capacity.The group claims rental rates have increased year-on-year but are slightly down from the previous quarter due in part to a significant increase in the number of new customers taking up introductory offers.James Gibson, Chief Executive Officer, commented: "Given the continuing uncertainties in the macroeconomic environment it is right to remain cautious. We are however encouraged by the continuing positive performance of this business."BS