The index value and the bar chart above are computed live from CoinGecko's free public API, using the same idea CoinMarketCap and Blockchain Center popularized: the share of the top 50 coins by market cap (excluding Bitcoin and major stablecoins) that outperformed Bitcoin's price over a trailing window. One difference: this uses a 30-day window instead of 90 days, because CoinGecko's free API only supports fixed windows of 1h/24h/7d/14d/30d/200d/1y — 90-day change isn't one of the free options, so 30-day is the closest accurate free equivalent.

Not included yet: Historical Values (Yesterday / Last Week / Last Month), Yearly High/Low, and a trend chart of the index over time. CoinMarketCap can show these because they save today's number to their own database every day, then look it up later. No free public API hands over that saved history for this specific index — it only exists once someone starts recording it daily.

This is buildable, though: since your site already has WPCode installed, I can write a small scheduled task that saves this index's value once a day into your WordPress database. After it's run for a week, a month, a year, this page can show real Yesterday / Last Week / Last Month / Yearly High-Low figures and a real trend chart — all still free, just built up over time instead of pulled from someone else's history. Say the word and I'll set that up.