Unit values represent a combined measure of the trend in the value and volume of exports. For non exchange-traded commodities and for products which are not homogeneous, such as NTAEs, unit values are generally the best (and often only) indicator of the underlying trend in price. The robustness of unit value data depends on the quality, accuracy and reliability of the data collected by the customs service or its equivalent. Under-declaring of values and volumes and the mis-recording or mis-classifying of cargoes can be a problem in many countries. In addition, customs categories are not always sufficiently detailed to reflect the diversity of products that may be classified under a single category heading. Thus, a "green bean" category will not only encompass a variety of different types of beans, but also lower value bulk beans and higher value "topped and tailed" beans.
Despite these caveats, the use of aggregated data from all exporting countries for each product category does provide a reasonably good indicator of the f.o.b. value of key NTAEs and of the trend in these unit values over time. Tables A1.14 to A1.19 present the trends in the nominal unit values of selected NTAEs in the fruit, vegetable, speciality and processed products categories. Figure 2.12 plots the trend in the nominal unit values of eight main fruits. Figure A1.1, in Annex 1, presents its equivalent in real terms, calculated using the IMF's MUV deflator.
Figure 2.12: Trend in nominal unit values for selected
Although all products for which we have calculated unit values are produced in a range of countries some with different seasons, weather and crop cycles still result in production fluctuations and these have an influence on the underlying trend in output. Where fruits are produced from tree crops, the response to higher or lower prices is much slower than for annual crops, and this can lead to greater volatility in export values. Notwithstanding these comments, it is noteworthy that overall trends in nominal unit values are relatively steady for a range of fresh fruit and vegetables.
If one fits trend lines to the data presented in Figure 2.12 it is apparent that the unit values of each of the fruits have charted slightly different paths over the ten year period. The unit values of grapes, papayas, avocados and pineapples have been fairly flat. This is despite the fact that export volumes have grown strongly over this period. (For example, world exports of avocados doubled, exports of grapes and pineapples increased by 80 percent and 70 percent, respectively, and papaya exports increased four-fold). The unit values for the counter seasonal fruits, such as apples, pears and melons have declined, but fairly gently, and still against a background of very strong export growth. In the case of apples, production is tending to shift to China from more traditional production areas in developed countries. China's production costs are low and, like Argentina and South Africa, it is able to continue to expand output. Both these factors are likely to contain any upward rise in unit export values.
In contrast, the unit values of mangoes have experienced a steep downward trend, with values declining from around U$875/tonne in 1992 to closer to US$590/tonne in 2001. During this same period world exports of mangoes have almost tripled, up from 220 000 tonnes in 1992 to closer to 600 000 tonnes in 2001. At these price levels, mango values are now much more closely aligned with those for other fruits, indicating that mango consumption is now more mainstream.
Similar data on the trend in the nominal unit values of selected vegetables are presented in Figure 2.13. If one fits a trend line to this data it is apparent that only one product - tomatoes - has seen unit values rise over this period. For the other vegetables there has been a slight decline, although this is somewhat more pronounced in the case of green beans. A comparable Figure for the trend in the real unit value of these vegetables is contained in Annex 1, Figure A1.2.
Figure 2.13: Trend in nominal unit values for selected vegetables, 19922001
Comparable data for selected speciality and processed products are presented in Figures 2.14 to 2.16 (and in Figures A1.3 to A1.5). The most marked trend has been in the nominal unit values of the selected processed products. All have experienced a downward trend in unit values and this is particularly pronounced in the case of canned mushrooms and apple juice concentrate. In the case of these latter two products, the entry of China into the export market has lowered unit values, a process which is expected to continue because China enjoys a comparative advantage in these products. Innovations in packaging and in the products themselves have helped to hold unit values steady in the fresh produce sector (see 2.5.2). In contrast, in the processed products sector there has been little innovation and products such as tomatoes, pineapples, sweet corn and tomato paste are packed and presented pretty much as they have been for many years. Some of the downward trend in unit values for these products can be attributed to this lack of product innovation.
Figure 2.14: Trend in nominal unit values for selected speciality products, 199220011/
1/ Including the high value fruit and vegetable products: strawberries and asparagus
Figure 2.15: Trend in nominal unit values for selected processed products, 19922001
Figure 2.16: Trend in nominal unit values for cut flowers and medicinal plants, 19912000
 Refer to the tables in
Annex 2 for more detailed data on the trends in individual commodities during
the past 10 years.|