According to a post by The H, about three quarters of the Linux kernel code are drivers, file systems and architecture-specific code, while there are plenty of comments and blank lines as well.
The first release of Linux had just 10,000 lines of code, while version 1.0.0 had grown to 176,250 lines by March 1994. In 2001 or about a decade ago, the Linux kernel (2.4) had about 2.4 million lines of code.
In an interview with German newspaper Zeit Online, Torvalds recently stated that Linux has become "too complex" and he was concerned that developers would not be able to find their way through the software anymore. He complained that even subsystems have become very complex and he told the publication that he is "afraid of the day" when there will be an error that "cannot be evaluated anymore."