The group of new HICs is comprised of hills, steep hills, accelerators, and one plateau (Germany, which is not surprising given that the break year is 1990). While volatility is higher, these countries have grown much faster than the United States: the growth differential average is 1.8-1.9%. The average of the ratio of the final GDP per capita and the minimum GDP per capita for the new HICs is about 9.8-9.9, almost three times larger than for the initial HICs. Thus, it is not surprising why these countries have joined the HIC group.

Finally, we take a look at those countries that remain middle income, or “still” MICs. Volatility is the highest among the three groups depicted here. Their average growth differs very little from the leading country or the initial HICs. The average ratio of final to minimum GDP is between 3.9 and 4, not much different from the ratio of the initial HICs. Finally, we see a wide range of growth patterns, including hills, plateaus, plains, accelerators, and mountains. We do not observe, however, steep hills, a very common categorization among new HICs or “escapees”.

**Table 9:  Time required to cross the lower and upper threshold of upper-middle countries**

|Country|Year for<br>lower<br>bondary of<br>|GDP to US<br>GDP - Lower<br>threshold|Year for<br>upper<br>boundary of<br>|GDP to US<br>GDP - Upper<br>threshold|Number of<br>years|Average growth<br>differential for 1950-<br>2008|Average growth differential for the<br>transition period from MIC to HIC<br>status<br>Average gro<br>reachin|wth differential until<br>g the upper UMIC<br>threshold|
|---|---|---|---|---|---|---|---|---|
||UMIC<br>**_Count_**|**_ries that have_**|UMIC<br>**_crossed both l_**|**_ower and upp_**|**_er thresholds_**|**_of the UMIC: 0.45 and 0.6_**|**_0 of US GDP per capita between 1950 and 2008_**||
|Austria|1955|0.46|1969|0.60|14|0.012|0.022|0.024|
|Finland|1951|0.45|1970|0.64|19|0.010|0.019|0.019|
|Germany|1953|0.46|1958|0.63|5|0.009|0.062|0.058|
|Hong Kong|1976|0.47|1982|0.62|6|0.027|0.055|0.032|
|Italy|1957|0.47|1968|0.61|11|0.010|0.028|0.030|
|Ireland|1980|0.46|1996|0.61|16|0.016|0.020|0.012|
|Japan|1966|0.46|1970|0.65|4|0.023|0.080|0.061|
|Singapore|1980|0.49|1990|0.61|10|0.025|0.030|0.026|
|South Korea|1994|0.45|2007|0.61|13|0.036|0.026|0.036|
|Spain|1973|0.46|2006|0.61|33|0.018|0.009|0.018|
|Taiwan|1991|0.46|2004|0.61|13|0.035|0.027|0.036|
|_Mean_|||||_13.1_|_0.020_|_0.034_|_0.032_|
||**_Count_**|**_ries that have_**|**_crossed both l_**|**_ower and upp_**|**_er thresholds_**|**_of the UMIC: 0.25 and 0.5_**|**_0 of US GDP per capita between 1950 and 2008_**||
|Greece|1957|0.26|2007|0.51|50|0.017|0.015|0.017|
|Hong Kong|1956|0.25|1978|0.50|22|0.027|0.034|0.029|
|Japan|1955|0.25|1968|0.54|13|0.023|0.058|0.057|
|Singapore|1969|0.26|1981|0.50|12|0.025|0.060|0.026|
|South Korea|1983|0.26|1997|0.50|14|0.036|0.049|0.039|
|Spain|1954|0.26|1975|0.51|21|0.018|0.036|0.034|
|Taiwan|1978|0.26|1993|0.51|15|0.035|0.048|0.040|
|_Mean_|||||_21.0_|_0.026_|_0.043_|_0.035_|

In Table 9, we list the countries that have crossed both the lower and upper thresholds of what we classify as upper middle income countries between 1950 and 2008.<sup>29</sup> On average, it took about 13.1 years (or 21 years, depending on the arbitrary relative income threshold we choose) to make the transition. A first look at the last three columns suggests that all these countries grew much faster than the United States. While this is not a rigorous test, Table 9 shows that the average growth differential until reaching the upper UMIC threshold is slightly

> 29 Estonia, for example, was left out because only a few years were available and the transition period from upper MIC to HIC spans most of the years available in the sample (1990-2006), thus, making the comparison of growth differentials across periods less meaningful.

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