In 2018, only 0.01% of ether was stolen in scams, worth $36 million, double the $17 million take for 2017. Scam activity increased dramatically in 2018 with nearly 75% of scamming activity taking place that year. Phishing, ponzi schemes and ICO exits are the most common scam types, but there are additional types of Ethereum scams, such as infection scams. The median amount sent to a scam was around 50% less than in the prior year. More sophisticated schemes dominated the second half of the year.”]
Source: https://blog.chainalysis.com/reports/the-rise-of-cybercrime-on-ethereum