ABANKROM, Ghana-Yaa Amekudzi bounces along dirt roads in a sport-utility vehicle from one village to the next as part of a $1 billion scramble by the world's top chocolate makers to fix the industry's most vexing problem. 

Demand for chocolate is stronger than ever, especially now that more consumers in China and India are buying bars and bonbons long considered an unaffordable luxury. But cocoa production is down, including a steep slide last year in Ghana, the second-largest cocoagrowing country. Cocoa prices have jumped nearly 40% since the start of 2012. 

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Global demand for chocolate rose 0.6% to a record 7.1 million tons in 2015, led by a 5.9% jump in Asia, according to research firm Euromonitor International. Cocoa production fell 3.9% to 4.2 million tons, estimates the International Cocoa Organization. The two totals are different because the ingredients in chocolate include sugar and often milk. 

In the growing season that ended Sept. 30, Ghana's cocoa production slid 18% from a year earlier because of disease, dry weather and shifts in government policy. Ivory Coast's cocoa harvest increased 2.8%. 

Many analysts expect production in those two countries, which grow about 60% of all cocoa, to drop in the current season, hurt by problems such as the old age of many trees, more bad weather and disease. 

While prices for nearly all commodities fell last year, cocoa rose about 10%. It was the best performer in the S&P GSCI commodity index. While prices slipped at the start of this year, the long-term surge has led companies such as Hershey, Nestlé SA and Lindt & Sprüngli AG to hike chocolate prices since the start of 2014. [...] 

Your task: 

Use demand and supply diagrams to support an explanation of the dramatic rise in the price of cocoa in the global market in recent years.