Table:
| ($ in millions) |  |  |  |
| --- | --- | --- | --- |
| For the year ended December 31: | 2019 | 2018* | Yr.-to-Yr. Percent/ Margin Change |
| Global Technology Services |  |  |  |
| External total gross profit | $9,515 | $10,035 | (5.2)% |
| External total gross profit margin | 34.8% | 34.4% | 0.3pts. |
| Pre-tax income | $1,645 | $ 1,781 | (7.6)% |
| Pre-tax margin | 5.8% | 5.9% | (0.2)pts. |
Paragraphs:
* Recast to reflect segment changes.
The GTS gross profit margin increased 0.3 points year to year to 34.8 percent, due to the benefits of workforce actions and the continued scale out of our public cloud. We continued to take structural actions to improve our cost competitiveness and are accelerating the use of AI and automation in delivery operations, including leveraging Red Hat’s Ansible platform. Pre-tax income of $1,645 million decreased 7.6 percent, driven primarily by the decline in revenue and gross profit, and a higher level of workforce rebalancing charges in the current year. Pre-tax margin of 5.8 percent was essentially flat year to year, with the 2019 pre-tax margin reflecting benefits from structural and workforce actions.
Question:
What was the increase / (decrease) in the Pre-tax margin from 2018 to 2019?
Answer: 5.8% - 5.9% = -0.1