Evolution of the bar strength. The top panel shows A calculated only within the virial radius R₂₀₀, while the bottom panel computes A over the entire system. Squares and solid lines denote halo b, circles and dashed lines denote halo d, and triangles and dotted lines denote halo e. The bottom panel also displays least‐squares fits to the data, suggesting that ﹩A\propto t^{\alpha }﹩, with ﹩\alpha =2.60\pm 0.03﹩ for the solid line, ﹩\alpha =2.02\pm 0.01﹩ for the dashed line, and ﹩\alpha =1.63\pm 0.02﹩ for the dotted line.