The nation's overall service industry activity increased 0.6 percent in November from the previous month due to increased mobile phone sales and active stock trading, marking the first rise in three months, according to a preliminary report issued Friday by the Ministry of International Trade and Industry. The seasonally adjusted tertiary sector index reached 103.5 against a 100-point benchmark based on 1995. While the sectors of transport, communications, finance, insurance and services contributed to the increase, the real estate, utilities and food service sectors declined. Communications increased 9.8 percent in November from the previous month and finance was up 3.5 percent. Real estate marked a temporary 4 percent drop due to a shorter period of subscription for low-interest loans by House Loan Corp. Electricity also fell 2.8 percent due to the warm November. A MITI Research and Statistic Department official said the overall trend is steadily rising with the help of sectors such as mobile communications and stock trading. In determining sustained growth from now on, MITI is watching services related to construction, corporate advertising and manufacturing equipment leasing to small and medium-size companies. , the official said. Meanwhile, the index of all industrial activity, including mining and manufacturing production, was up 0.6 percent to 101.2, also marking its first month-on-month increase in three months.