By Lykke E. Andersen
''During most of the history of mankind, average incomes across the globe
amounted to somewhere between $1 and $2 per day, and income growth was
only marginally above zero, averaging about 0.033% per year from year 0
to year 1868, and probably even less during the preceding millennia. In
the hundred year period from 1868 to 1968, however, real per capita
income growth suddenly increased forty-fold to about 1.43% per year, and
when I was born average per capita income in the world had reached
about $10/day. During my life-time, income growth has averaged 1.96%,
implying that average per capita GDP in the world is now above $20/day.
Growth rates have kept increasing steadily, reaching an average of about
2.94% per year in the first decade of this century. Such growth rates
are unprecedented in the history of our species.''