Occidental Petroleum Corporation (NYSE:OXY) announced core income for the fourth quarter of 2013 of $1.4 billion ($1.72 per diluted share), compared with $1.5 billion ($1.83 per diluted share) for the fourth quarter of 2012. Net income was $1.6 billion ($2.04 per diluted share) for the fourth quarter of 2013, compared with $336 million ($0.42 per diluted share) for the fourth quarter of 2012. The fourth quarter of 2013 includes an after-tax gain of $665 million ($0.83 per diluted share) from the sale of a portion of an investment in the General Partner of Plains All American Pipeline, L.P., and an after-tax charge of $395 million ($0.49 per diluted share) related to the impairment of certain non-producing domestic oil and gas acreage. The fourth quarter of 2012 included an after-tax charge of $1.1 billion ($1.41 per diluted share), almost all of which was related to the impairment of gas assets in the Midcontinent. Net income for the twelve months of 2013 was $5.9 billion ($7.32 per diluted share), compared with $4.6 billion ($5.67 per diluted share) for the same period in 2012. After excluding the non-core items, 2013 core income was $5.6 billion ($6.95 per diluted share) for the full year of 2013, compared with $5.8 billion ($7.09 per diluted share) for the same period in 2012. In announcing the results, Stephen I. Chazen, President and Chief Executive Officer, said, "We had strong results in our domestic program in 2013. We grew our domestic liquids production by 15,000 barrels per day, or 5 percent, to 343,000 barrels per day on a year-over-year basis. Our focused drilling program and emphasis on efficiencies yielded a 24-percent reduction in our drilling costs relative to 2012 and a 17-percent improvement in operating costs, resulting in domestic oil and gas operating expenses of $14.43 per BOE for the year. Our domestic proved liquids reserve replacement was 228 percent and we replaced all of our domestic gas production with our drilling program.