The LSAT has a scaled score range from 120-180, which corresponds to a bell curve. However, this scale score is based on how many questions you missed across the four scored sections of the LSAT. Mosts modern LSATs have 100 (plus or minus one) questions on them: 50 from logical reasoning, 23 from logic games, and 27 from reading comprehension. Each LSAT has its own raw to scale score conversions, which you can find on each PrepTest's page. Below are explanations for each part of the raw score to scale score conversion and how they map on to the bell curve.
For each scaled score from 120-180, there is a corresponding raw number of missed questions and place on the bell curve.
We've focused in on the scores between 158 and 165 because those scores are the first and second standard deviations, respectively, above the average score of 151. As you read from left to right starting at the scale score, you see the lowest and highest raw score (the number of correctly answered questions), then the approximate number of missed questions, the cumulative amount of test-takers who scored above the scale score, and finally the number of standard deviations. As you continue looking left to right into the gradient portion of the bell curve, you see that approximately 13.59% of all test-takers fall between the scale scores 158 and 165. The thick black lines roping along the standard bell curve are taken from the actual scale score distribution for all test-takers on a real LSAT between 1997 and 2004.
People often talk about their LSAT score in terms of how many people they scored better than. For instance, a 165 scale score is in the 97.7th percentile, meaning that someone with that score did better than 97.7% of all people who took the test (and only worse than 2.3%).
This information is available in the graph on the "Cumulative %" line: take 100% and subtract the given value and that will be the percentile that corresponds to that scale score. We've marked each standard deviation with this data, so you can quickly estimate the percentile for each scale score.
Another percentage that people might talk about is tied to how many people actually received a given score. For instance, only about 0.02% people score a perfect 180, which works out to fewer than 25 people in any given year.
On the left is a close-up of the graph with 0-4% along the y-axis. This does not represent the scale score ranking, but rather the percentage of test-takers who scored that specific scale score. For example, at 165, the LSAT bell curve intersects the percentage axis near 1.4%. This does not mean that someone who scored a 165 is in the top 1.4% of all test-takers, it means that around 1.4% of the 151,400 people who took an LSAT in 2009--or 2,150 people--received an LSAT score report with 165.
The 99th percentile--the scale score at which a test-taker has scored more points than 99% of all other test-takers--is usually distributed on the bell curve around 172. We zoomed in within that 99th percentile to show you how cumulatively adding the number of people with scores from 180-172 breaks the 99th percentile barrier. Essentially, when you add the test-takers who scored a 180 to the ones who scored 179, 178, etc, the subtotal becomes 1% of the overall when the 172 people are added.
Data shows that scores for repeat test takers often rise slightly. Most people take the test only once; last year 70.2% of the total number of test takers took the LSAT just one time; 24.5% took the test twice; and approximately 5.3% took the LSAT more than twice.
Keep in mind, however, that law schools will often consider all of your LSAT scores from the past 5 years, rather than simply count the highest. If you have two wildly different scores, you can write a supplemental essay to explain what happened on the lower score.
That said, be sure to prepare well so you don't have to retake the LSAT!
This question is relatively easy to answer for a single law school: load up the school's website and check their "Entering Class Profile" information for the GPA and LSAT of the middle 50% of accepted applicants. Above is a graph comparing the predicted acceptance rate for two fictional students, Diane and James, with their LSAT score as the independent variable. The data is taken from the law school calculator. It's pretty self-explanatory, but here's a blog post on how to use it if you want a reference point.