All data is in percentages.
Each column represents a special time period with Pioneer being the earliest and Sedentary the latest. The problem is to order these houses in terms of time from early to late. Archaeologists look at types of design styles and can order houses such as these because those design styles change over time. It is similar to the changes in American stoves from gas to electric to microwave. As a new style or product become popular, the frequency of it increases while earlier styles or products decrease in frequency.