While some professionals recommend a 1-2% keyword density (1-2 keywords per 100 words), there is really no set rule or guideline around keyword density. In fact, most SEO experts do not believe that keyword density is even considered a ranking factor anymore.
The best rule of thumb is to not keyword stuff. You want to include enough keywords that you signal to Google the topical relevance of your content, but not so many that the readability of the content is impacted. So, it really is a judgment call. If you read over your copy and it sounds unnatural, or may even deter a user from continuing to read, that is a good indicator to update your keyword targeting.
It is also important to keep in mind that Google rewards content that is created to benefit users, not content that is created solely for rankings. If you are including too many keywords, Google may even penalize your page for it. Always put the users’ benefit above all else and Google will reward your content accordingly.
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