Question: what was the percentage increase in zero day vulnerabilities in 2015?
Answer: In the 80-page report, the firm discovered a total of more than 430 million unique pieces of malware in 2015, up 36 percent from 2014. A new zero-day vulnerability was discovered, on average, once each week in 2015. Symantec puts the cumulative number at 54, which is a 125 percent increase from the year before.