Economics doubt

In Indian economy section of economics should we remember every single statistic given there or would it be sufficient to remember the general trend and the current figures

for eg. in the table occupational structure for india the distribution of work force in primary sector is given as

1951            1961         1971        1981          1991            2001     2004

72.1            71.8           72.1          68.7           62.7             59.3     52.7        (percentage)

Now should we remember all the figures given or is it sufficient to remember the general trend that percentage of work force in primary sector is decreasing and that it is 52.7% in 2004