Idaho uses the English Language Arts and Mathematics tests from the Smarter Balanced Assessment Consortium (SBAC) for the Idaho Standard Achievement Tests. ISAT results have been reported almost exclusively as "percent proficient or above" statistics (i.e., the percentage of Idaho students who performed at the "A" level). This paper illustrates how a traditional normative statistic using scale scores--percentiles--can provide informative descriptions of student achievement trends. The 10th, 25th, 50th, 75th and 90th percentiles for the ISAT 2015, 2016, and 2017 English Language Arts and Mathematics tests for grades 3-8 and 10 were examined. These five percentiles provided an across-the-board look at student achievement (i.e., High, High Average, Average for Grade Level, Low Average, and Low performing students) and at how achievement has changed over time and graphically via boxplots and line graphs. Between 2016 and 2017, Idaho lost 26 percentile points statewide in English language arts but gained three in mathematics. Statewide from 2016 to 2017, the English language arts percentiles of Idaho's High and High Average performing students increased while the percentiles of Idaho's Average, Low Average, and Low performing students decreased. The mathematics percentiles of Idaho's High, High Average, and Average performing students increased while the percentiles of Idaho's Low Average and Low performing students decreased. These achievement trends in terms of percentiles could become an informative element of Idaho's comprehensive accountability system. (Contains 7 references, 2 tables, and 16 figures.)