Senke diagramm als Choropleth-Infografik mit Heatmap

Data visualization infographic titled "Heatmap Example" using a CHOROPLETH MAP as the dominant visual element, focused on regional shading to show trend over time. Create a clean editorial data journalism layout with one large choropleth map of a plausible country or continent divided into clearly labeled regions in English, plus a compact horizontal timeline beneath it showing 5 yearly snapshots: 2020, 2021, 2022, 2023, 2024. Each map snapshot uses a monochrome ink gradient from very light gray to deep black to represent increasing values, with a crisp legend labeled in English: "Low", "Medium", "High", "Illustrative index". Add sharp region labels, legend ticks, year labels, and scale markers in English. Ensure no misleading scale manipulation and no truncated legend range.

Use realistic illustrative values to imply a trend: 2020 national index 42, 2021 index 47, 2022 index 53, 2023 index 61, 2024 index 68. Show regional variation with plausible 2024 values such as "North 74", "South 58", "East 66", "West 71", "Central 64". Include subtle mini arrows or sparkline indicators near the map to reinforce upward trend.

Add 4 key insight callouts around the chart, each with a small icon, a headline number, and a short interpretation in English:
1. icon: upward arrow, headline: "68", text: "National illustrative index reached its highest level in 2024." 
2. icon: map pin, headline: "+32%", text: "North shows the strongest illustrative gain since 2020." 
3. icon: bar cluster, headline: "16 pts", text: "Gap between highest and lowest regions remains moderate." 
4. icon: clock, headline: "5 years", text: "Trend shows steady broad-based regional darkening over time." 

Add a small source / data-note strip at the bottom in English with exact text: "Data note: Illustrative example only. Figures are plausible mock values for visualization design and are not sourced statistics." Add a small legend note: "Darker shade = higher illustrative value." 

Visual style: monochrome ink palette, black, charcoal, slate, warm gray, off-white background; restrained newsroom sophistication; precise typographic hierarchy; elegant negative space; subtle hairline borders; high-contrast labels; editorial data journalism illustration, FT / Bloomberg-grade chart aesthetics, vector-clean infographic layout. All text MUST be written in English (array). Every heading, label, caption, legend and metric name in the image must be in English — not English. Spell each English word correctly using English characters and diacritics. Numbers stay as digits, no fake authoritative sources cited, no watermarks Numbers labeled "illustrative" unless the user supplied specific sourced data. No fake authoritative sources cited (do not invent "Source: Reuters 2025" — use "Illustrative example" instead). No misleading axis truncation or scale manipulation.