There were 3.7 million job openings at the end of January, a small increase from the previous month, the U.S. Labor Department said Tuesday. On the last business day of January, there were 3.69 million job openings, the department said releasing preliminary figures. On the last business day of December, there were 3.61 million job openings, the department said. Job openings were slightly higher in construction and manufacturing and modestly higher in retail trade. Job openings for professional and business services jumped by 101,000 in the month to 676,000, the monthly report said. The hiring rate and separation rate -- the percentage of employees hired or leaving a job -- were unchanged at 3.1 percent and 3 percent, respectively. In the construction sector, the separation rate -- also known as the turnover rate -- rose from 4.6 percent in December to 5.4 percent in January, but the hiring rate, just ahead of an seasonal increase in construction projects, also rose, climbing from 4.9 percent to 5.6 percent.