Referring to a certain value when generating a new variable

Hello,

I want to refer to a certain value when generating a new variable.

My panel dataset looks as follows:

year	country_num	gdp_deflator
2002	36	62.241596
2003	36	64.179539
2004	36	66.304613
2005	36	68.822255
2006	36	72.326928
2007	36	75.951745
2008	36	79.388969
2009	36	83.359849
2010	36	84.332893
2011	36	89.606027
2012	36	91.269587
2013	36	91.15623
2014	36	92.504954
2015	36	91.996491
2016	36	91.50615
2017	36	94.923676
2018	36	96.713572
2019	36	100
2020	36	101.96804
2002	50	81.621139
2003	50	86.368075
2004	50	90.308304
2005	50	94.450169
2006	50	100
2007	50	106.47126
2008	50	114.84093
2009	50	122.60918
2010	50	131.36919

country_num is the ISO 3166-1 numeric of the regarded country (36: Australia, 50: Bangladesh). In total, my dataset consists of 24 countries and for each country there are values for each year from 2002 to 2020.

gdp_deflator contains the GDP deflator for the country in the respective year. However, the base year varies by country.
Hence, I want to calculate a new GDP deflator which has the same base year (2010) for every year and country.

To do so, I use the following formula for every year t: new_deflator(t) = 100 * gdp_deflator(t) / gdp_deflator(2010)

Thus, for every country and year, I want to divide the GDP deflator of the year by its GDP deflator of the year 2010. For example, the calculation for the first observation would be 100 * 62.241596 / 84.332893 = 73.8.

How can I implement this formula when using generate or egen or even replace?

For example, I tried something like

Code:

generate new_deflator = 100 * gdp_deflator / gdp_deflator[year==2010]

, but this did not work.

Thank you for your help!