  We present a quantitative characterisation of the fluctuations of the
annualized growth rate of the real US GDP per capita growth at many scales,
using a wavelet transform analysis of two data sets, quarterly data from 1947
to 2015 and annual data from 1800 to 2010. Our main finding is that the
distribution of GDP growth rates can be well approximated by a bimodal function
associated to a series of switches between regimes of strong growth rate
$\rho_\text{high}$ and regimes of low growth rate $\rho_\text{low}$. The
succession of such two regimes compounds to produce a remarkably stable long
term average real annualized growth rate of 1.6\% from 1800 to 2010 and
$\approx 2.0\%$ since 1950, which is the result of a subtle compensation
between the high and low growth regimes that alternate continuously. Thus, the
overall growth dynamics of the US economy is punctuated, with phases of strong
growth that are intrinsically unsustainable, followed by corrections or
consolidation until the next boom starts. We interpret these findings within
the theory of "social bubbles" and argue as a consequence that estimations of
the cost of the 2008 crisis may be misleading. We also interpret the absence of
strong recovery since 2008 as a protracted low growth regime $\rho_\text{low}$
associated with the exceptional nature of the preceding large growth regime.
