Historic volatility in the price of crude oil appears to be easing due to rising prices since the beginning of the year, according the latest data from the U.S. Energy Information Administration (EIA).

The chaotic market conditions that marked the start of 2016 were driven by high uncertainty related to supply, demand and inventories. EIA figures show that crude oil price volatility has declined since its peak in March.

“Prices have risen as concerns about future economic growth have abated and as inventory growth has slowed since the start of the year,” the EIA said.

The 30-day measure of oil price volatility (calculated as the standard deviation of daily percent changes in crude oil prices over the previous 30 trading days) reached a high of 45 percent on March 4 before falling to 33 percent on April 18, the EIA said.

March saw the highest volatility levels since 2009, when crude oil prices were falling in response to the financial crisis and a drop in demand, the EIA said. The recent decline in oil prices has resulted in volatility levels closer to the 2015 average of 27 percent.

Volatility often reflects market uncertainty about both the current and future value of a commodity. Daily volatility is often driven by the release of new economic or supply information, changes in market expectations or unanticipated events that can cause large price adjustments.

The EIA said reasons for volatility in crude oil prices include uncertainty about:

• Future production levels in key oil-producing nations
• Global economic growth, particularly in China and other emerging market economies
• Growth in U.S. gasoline demand following higher consumption levels in 2015
• Crude oil inventories and storage capacity constraints

Historically, volatility also increases during unexpected interruptions in oil supply, such as the disruptions during the 1990 Gulf War, the aftermath of hurricanes in the Gulf of Mexico and the 2011 civil war in Libya, the EIA said.

Another measure of volatility is the monthly trading range—the difference between the high and low closing oil prices in a given month. In January of 2016, Brent crude oil spot prices closed at a low of $26 per barrel and a high of $36 per barrel. This $10-per-barrel trading range was higher than the range of any month in 2015.

“The magnitude of the trading range compared with the average monthly price was 33 percent in January, the highest since 2008,” the EIA said. The trading range for April dropped to 13 percent, the EIA said.