DDoS attacks have been around since the inception of the web, but have evolved over time to become more sophisticated and powerful. The data show that the DDoS continues to be a global threat, with alarming increases in attack size this year and the last quarter was included in the 3-3.5 Gbps range. The largest DDoS attack size had a peak at 191Gbps and occurred in August 2013, this data is considered concerning because it has broken through the psychological threshold of alert estimated on 100Gbps.
Source: https://thehackernews.com/2013/10/ddos-attacks-serious-unstoppable-menace.html