Researchers who analyzed data on 28 different types of cancer in 188 countries from 1990 to 2013 have found that worldwide, a greater percentage of deaths are now caused by cancer. The report, conducted by the Global Burden of Disease Cancer Collaboration group and published Thursday in JAMA Oncology, found that between 1990 and 2013, the proportion of deaths caused by cancer rose from 12 to 15 percent, and the years of life lost to cancer increased by 29 percent.