First, it is important to look at the admissions requirements of schools you are applying to because some of the schools only look at some aspects of the GRE. For example, as of 2016, UC Davis only takes into account the Quantitative score. Second, it is useful, but only to a certain extent, to look at the statistics from previous admitted classes, which I have exemplified below (with links).
Quick note about GRE scoring: the scores represent which percentile you fall into, or your ranking among other test-takers. Percentiles are determined from the raw test scores of students of the years before you, where the relationship of percentile to raw scores differs for the verbal, quant, and writing sections. Percentiles are recalculated every few years. Keep in mind that the test is not identical every year and there are many versions per year. Data is collected and analyzed for each question in order to improve the exam. Questions change slightly every year, and the readers (who score the writing portion) are different for each person, may change from year to year, and prompts/question change from year to year. Finally, these published class GRE statistics reflect the scores of the entire class after matriculation (accepting the admission offer), meaning they do NOT account for the scores of ALL who were offered the first seats; i.e. they do not represent the scores of students who declined an admission offer. Similarly, the scores DO represent the fraction of students who were waitlisted and were able to get a spot after the other students declined the admission offer. The published scores do NOT represent the minimum score required for entrance, as you will also see with WSU who published range along with the average.
Below is the comparison of my scores to the 4 schools I applied to. I was offered admission to UC Davis and OSU, offered (but did not pursue) an interview to WSU, and denied admission from CSU. Notice how I was below the average for UCD's quantitative score (this is the only one UCD considers as of the 2016 cycle) yet was accepted there, and how even though I exceeded CSU's GRE scores they still denied me admission.
*OSU only published the average of the cumulative GRE averages (average of the verbal, quant, and writing scores) for the admitted class.
**WSU is the ONLY school that published a range along with its averages (see below).
***CSU only published the average of raw scores; I converted it to percentiles using the conversions in the 2016-17 GRE guide (attached as PDF file at bottom of post- see page 22 in the guide).
Note that all schools publish the AVERAGE scores of the entering class. Recall that an average is made up of all the scores, and for example, an an average of 50 can be made up of two scores of 50&50, 25&75, or 100&0. Note that no standard deviation was published along with the averages, so we have no idea about the distribution of the scores around the average. Washington State was the only school that published the range (**):
The range turns out to reveal incredibly important information. Notice how large the range is. It might as well be 0-100! The take-home-message is that there are MANY things that factor in to making you an awesome applicant, and the GRE may not be a huge one in the grand scheme of the admissions eye. Thus, I would only recommend retaking your GRE if you are SIGNIFICANTLY below the average, and/or if you do not have a strong GPA and need to balance it out with a strong GRE.
Links to admissions statistics:
Oregon State U CVM:
Washington State U CVM:
UC Davis SVM:
Colorado State U CVMBS:
Below is the GRE guide that shows the conversion of the raw score to a scaled percentile. See page 22.