The dividend yield of the S&P 500 has decreased in recent years due to the dominance of growth stocks in the index and stock prices outpacing dividend growth rates. With the index now yielding just 1.3%, investors looking for stocks to boost their passive income stream may want to consider higher-yielding options.Chevron (CVX 1.20%), United Parcel Service (UPS 2.47%), and the chemical specialist Dow (DOW 2.15%) yield 4.5%, 5.3%, and 7%, respectively, at the time of this writing. All three companies have sol ...