Take into account consumer price indices v0

[martincollignon]

EXIOBASE relies on numbers from the past. The data we're currently using is from 2011.

To improve the accuracy of our carbon equivalent numbers, we should take into account changes in prices since 2011, and then the currency exchange from 2011 as EXIOBASE is in €.

Steps to get the adjusted price:

1. Use index from the proper country (fallback:OECD average data)
2. Use index from the latest available date
3. Use index from the most precise COICOP category (fallback: total CPI index)
4. Convert the price adjusted by the indexes to EUROS

Development priority

1. Convert prices to Euros
2. CPI from the proper country from 2019

Structure of files:

exchangerate.yml:

• currency pair
  --- year
  ---- month

consumerpriceindices.yml

• country (ISO2)
  -- COICOP category
  --- year
  ---- month

Current data available:

• 2011 exchange rates to Euros (Source EUROSTAT)
  2011_euro_exchange_rates.xlsx

• CPI by country by month by COICOP category (Source: OECD)
  CPI_indices_OECD.xlsx

[corradio]

@pierresegonne: @martincollignon and I wrote a brief here to specify better the task:
https://www.notion.so/tmrow/CPI-brief-a125471890544282a657b42b11a2bf21

@martincollignon will follow up with you!

[pierresegonne]

@martincollignon do you know from where exactly you obtained the OECD excel file? I'll add it to the PR once I have the link :)

[martincollignon]

https://stats.oecd.org/Index.aspx?DataSetCode=PRICES_CPI#

Without knowing which numbers you have in the PR, I've pulled the latest ones just to make sure here.
6cbdd8cd-f015-448f-a1c4-54a9cb63c987.xlsx