Table:
|  | 2019 | 2018 | 2017 |
| --- | --- | --- | --- |
|  | €m | €m | €m |
| Sales of goods and services to associates | 27 | 19 | 37 |
| Purchase of goods and services from associates | 3 | 1 | 90 |
| Sales of goods and services to joint arrangements | 242 | 194 | 19 |
| Purchase of goods and services from joint arrangements | 192 | 199 | 183 |
| Net interest income receivable from joint arrangements1 | 96 | 120 | 87 |
| Trade balances owed: |  |  |  |
| by associates | 1 | 4 | – |
| to associates | 3 | 2 | 1 |
| by joint arrangements | 193 | 107 | 158 |
| to joint arrangements | 25 | 28 | 15 |
| Other balances owed by joint arrangements1 | 997 | 1,328 | 1,209 |
| Other balances owed to joint arrangements1 | 169 | 150 | 127 |
Paragraphs:
29. Related party transactions
The Group has a number of related parties including joint arrangements and associates, pension schemes and Directors and Executive Committee members (see note 12 “Investments in associates and joint arrangements”, note 24 “Post employment benefits” and note 22 “Directors and key management compensation”).
Transactions with joint arrangements and associates
Related party transactions with the Group’s joint arrangements and associates primarily comprise fees for the use of products and services including network airtime and access charges, fees for the provision of network infrastructure and cash pooling arrangements.
No related party transactions have been entered into during the year which might reasonably affect any decisions made by the users of these consolidated financial statements except as disclosed below.
Note: 1 Amounts arise primarily through VodafoneZiggo, Vodafone Idea, Vodafone Hutchison Australia and Cornerstone Telecommunications Infrastructure Limited. Interest is paid in line with market rates.
Dividends received from associates and joint ventures are disclosed in the consolidated statement of cash flows.
Question:
What is the difference between 2018 and 2019 average sales of goods and services to associates?
Answer: [(27+19)/2] - [(19+37)/2]  = -5