Pulp sales volume decreased slightly to 1,428,638 ADMTs in 2010 compared to 1,445,461 ADMTs in 2009. Average pulp sales realizations increased by approximately 50% to €591 per ADMT in 2010 from €393 per ADMT in 2009 primarily due to significantly higher pulp prices.
Costs and expenses in 2010 increased to €732.8 million from €632.6 million in 2009, primarily due to higher fiber costs.
Our overall fiber costs in 2010 increased by approximately 24% from the same period in 2009, primarily due to higher fiber costs in Germany resulting from lower harvesting levels, combined with increased demand for wood from the energy sector for heating and bio-energy purposes. Fiber costs at our Celgar mill increased marginally from the prior year.
For 2010, we recorded operating income of €167.7 million, compared to an operating loss of €12.8 million in 2009, primarily due to higher price realizations resulting from higher pulp prices.Interest expense in 2010 increased to €67.6 million from €64.8 million in 2009, primarily due to accretion expense related to the exchange of our convertible notes, partially offset by reduced levels of debt associated with our Stendal mill. Our Stendal mill recorded an unrealized gain of €1.9 million on its interest rate derivatives at the end of 2010, compared to an unrealized loss of €5.8 million last year due to a small increase in European interest rates. We recorded a foreign exchange loss on our debt of €6.1 million in 2010, compared to a gain of €2.7 million in 2009. In 2010, the noncontrolling shareholder's interest in the Stendal mill's income was €8.5 million, compared to €9.9 million of the Stendal mill's loss last year. In 2010, Operating EBITDA increased fivefold to €224.0 million from €41.4 million in 2009. For a definition of Operating EBITDA, see page 4 of this press release and for a reconciliation of net income to Operating EBITDA, see page 8 of the financial tables included in this press release.