Chart Type for Proportional / Percentage. Keywords: waffle, percentage, proportion, progress, filled, grid. Best Chart: Waffle Chart. Secondary Options: Pictogram, Stacked Bar 100%. When to Use: Showing what fraction of a whole is filled; percentage progress in a visually engaging and accessible format. When NOT to Use: More than 5 categories (use stacked bar); exact values matter over visual proportion; very tight space. Data Volume Threshold: 10×10 grid standard (100 cells); for > 5 categories switch to stacked 100% bar. Color Guidance: 3–5 categories max. 2–3px gap between cells. Each category a distinct accessible color pair. Accessibility: AA — Better than pie for accessibility. Percentage text label always visible. Each cell has aria-label.. A11y Fallback: Percentage text always visible; grid cells labeled with aria-label value; provide legend. Library: D3.js, React-Waffle, Custom CSS Grid. Interactive Level: Hover.