The Conference Board reported that its help-wanted advertising index (1967 equals 100) rose to 144 last month, four points higher than October's and seven points above the year-ago level of 137. The index measures the volume of classified advertising in 51 major newspapers across the nation. Want-ad volume declined in the East South Central region, at a rate of 0.7%, and in New England, at 0.4%. It rose, however, in the East North Central region at a rate of 7.9%. Other regions recording increases included: Middle Atlantic, 5.8%; Mountain, 4.1%; South Atlantic, 3.3%; Pacific, 2.8%; West North Central, 0.7%, and West South Central, 3.3%.