Calculated correlation based on monthly, quarterly and yearly time series using 12 months, 10 quarters and 5 years on a rolling basis. Plotted below against copper market share of exports.
Following conclusions can be drawn:
- For shorter time intervals you get more noise, but an a yearly basis you get very high correlation (i.e. low correlation coefficient smaller than -80%)
- There seem to be periods with high correlation regimes (1992-1998, 2003 to present)
- Correlation breaks-down in 1989-2991 and 1999-2002