Only 25% of users update their anti-virus databases every day – this gives lots of opportunity for new infections. In just a week and a half my friend managed to pick up 78 (!) malicious programs: Trojan 36 (!) Trojan-Clicker 2 (?)Trojan-Downloader 11 (!) Trojan-downloader), AdWare 26 (?) RiskWare 3 (?) Viruslist.com: 36 (?) Trojan.com.com)”]
Source: https://securelist.com/how-much-malicious-code-is-really-out-there/29889/