Gradually declining benchmark interest rates have lured some investors back toward real estate investment trusts (REITs) over the past year. Those lower rates make it easier for REITs to purchase more properties, while shrinking yields for CDs, bonds, and Treasuries drove many income-focused investors back toward higher-yielding dividend stocks again.But amid a good year for REITs, one that was left out in the cold was Sun Communities (SUI -0.88%), which mainly invests in manufactured home communities, RV c ...