University and college attendance refers to the number of people attending universities, teacher-training colleges, and professional schools, divided by the total population of relevant age, then multiplied by 100 to generate a percentage. The age group is five years beyond the usual completion of secondary schooling. Admission to universities and colleges requires the successful completion of secondary school or the equivalent. University and college attendance measures a country's educational trends, including its commitment to advanced education. A larger number indicates a greater share of people pursuing degrees beyond the secondary level.

United Nations Educational, Scientific, and Cultural Organization (UNESCO) database, 1998; (www.unesco.org).

Why are they important?
You might think statistics are nothing more than dull, dry catalogues of numbers. In fact, they are indispensable to the way we understand our world. Amounts, rates, and other numerical data can convey a great deal of information, especially when we use them to make comparisons between things.
In the Encarta 99 World Atlas, statistics answer such questions as where? how many? how much? and how fast? They may also inspire you to wonder: why? Interesting and sometimes surprising stories lie buried in the tables and graphs. A little digging in the companion articles of the Atlas reveals answers to many of the questions that statistics may raise.
Why, for example, should so many merchant ships be registered in Liberia, a small West African country with few ports and a coastline of limited extent? Go to the section about the economy of Liberia and find out. How come China raises such an enormous number of pigs? The article about pigs tells why.

Tables
The tables give the values of more than 150 different statistical measures for the countries of the world, which are listed either by rank, from number 1 on down, or in alphabetical order.

Graphs
You can also look at the information in a series of bar graphs. A button at the lower left corner of the graph lets you switch between two versions: one is plotted against a linear scale and the other against a logarithmic scale. In a linear-scale graph, the value of each bar is read against a vertical axis that increases by intervals of equal value, just as a ruler is marked in regular intervals of centimetres or inches. Linear-scale graphs are easy to interpret, because a bar that stands for 500 units of measurement, for example, is twice as high as a bar that stands for 250 units.
But in many of the things that statistics measure, the countries of the world differ tremendously, and linear-scale graphs may become very hard to read. The population of India, for instance, is more than 93,000 times as large as that of the Pacific island nation of Tuvalu. In a linear-scale graph in which these values were shown in their true proportions, the Tuvalu bar might be too tiny to read and the India bar could go right off the chart.
To compare values that differ by so much, a logarithmic-scale graph is far more useful. In this sort of graph, the vertical axis is marked in intervals that increase in value by the power of ten, so that successive ticks stand for 1, 10, 100, 1,000, 10,000, ..., rather than for 1, 2, 3, 4, 5, and so on. In the Encarta World Atlas, this produces a "flatter" graph in which the heights of the bars rise gradually from left to right. In contrast, the typical linear-scale display rises steeply at its upper end.

Maps
The set of statistical maps illustrates the same data and puts them in a spatial context, so you can make comparisons between geographical neighbours at a glance. Colours indicate where a country ranks: the lightest yellow countries have the lowest positive values for the statistical indicator chosen, and the darkest orange countries have the highest. For some measures, such as balance of trade or rate of population growth, values may be less than zero. A range of purples indicates these negative numbers. Sometimes no data are available, and then the country is coloured grey.