SEOUL, July 27 (Reuters) - South Korea’s economy expanded at the fastest annual pace in a decade in the second quarter thanks to a pick up in consumption, data from the Bank of Korea showed on Tuesday. Gross domestic product (GDP) expanded 5.9% year-on-year in the April-June after rising 1.9% in the first quarter, just shy of 6.0% growth tipped in a Reuters survey. Asia’s fourth-largest economy grew a seasonally adjusted 0.7% in the second quarter from three months earlier, matching a 0.7% rise seen in the survey, advanced estimates from the BOK showed. Reporting by Cynthia Kim; Editing by Sam Holmes Our Standards: The Thomson Reuters Trust Principles.