CDs were originally able to store more data than computer hard drives but hard drives now far exceed CD capacity. By 2007, over 200 billion CDs had been sold worldwide, though sales have declined as digital storage and distribution has increased. CD pros include not being able to crash and easy use, while cons are being scratchable and having a small storage capacity. MP3s use lossy compression to reduce file sizes but also reduce audio quality slightly. MP3 pros are small file sizes and wide compatibility, while the con is potential quality loss. WAV files are uncompressed and highest quality but also largest in size, with pros being quality and support, and cons being large file sizes and slow importing.