The general wisdom is that 70% of positions are found through networking. Some companies prefer to hire only people that are recommended to them by employees or other people they trust.
Another 15% of positions are found through job agencies. Some specialize in specific areas like technology, others are far more inclusive.
5% of jobs are estimated to be obtained through online applications. There is debate about this statistic. As online job sites have flourished, does it make sense that so many companies would spend money there? Some maintain that the number is more like 20%.
If you followed the math above, something doesn’t add up. I either got to 90% or 105%. Either way, there are other strategies people employ: value proposition letters, informational interviews, job fairs, etc.