It was a year to forget, as far as Sector Leaders was concerned. The most elite of IBD’s stock screens lost 11.8% for the year going into Thursday’s final trading session of 2015. That compares unfavorably to the S&P 500, which eked out an 0.2% rise during the same period. Most of the damage was done in the second half. Sector Leaders fell 16.9% in the past six months vs. a flat move by the large-cap benchmark.