About 55 percent of all e-mails sent worldwide are unwanted ad or spam mails, according to security software business Kaspersky. The United States are the biggest source of spam, accounting for 15.2 percent of global spam traffic. Russia was in second place (6.2 percent) with Vietnam and China sharing third place (6.1 percent). The positive outlook being that the proportion of spam in e-mail flows was 55.28%, which was 11.48 percentage points lower than in 2014.
From a post by Statista’s Dyfed Loesche, this chart shows the top 10 countries from which spam originated in 2015.
Source: https://www.statista.com/chart/4338/most-spam-messages-originate-in-the-us/