Complex sentence: Since entering the local news race, WSHM struggled to make a dent in the ratings of NBC affiliate WWLP and WGGB, however its ratings grew substantially across the board during the May 2009 sweeps period, to within decimal points of WGGB in several key demographics.
Split into simpler sentences: Since entering the local news race, WSHM has struggled to make a dent in the ratings of NBC affiliate WWLP and WGGB. However, its ratings grew substantially across the board during the May 2009 sweeps period to within decimal points of WGGB in several key demographics.