More people started using the computers in the late 1990s and early 2000s. Computers were getting more complex just as fast. People saw that they could use malware to get useful information now, like passwords and credit card information. So, more programmers started writing malware. The number of malware programs on the Internet has grown very quickly ever since then the late 1990s and is still growing today. Experts think that 31.5% of the world's computers have some type of malware installed.