| 52 weeks to
29 March
2013 | 52 weeks to
28 March
2014 | 52 weeks to
27 March
2015 | 52 weeks to
1 April
2016 | 52 weeks to
31 March
2017 |
|---|
| Revenue growth | +1.0% | +7.9% | +6.9% | +1.7% | +7.2% |
| Gross margin | 54.8% | 53.7% | 53.2% | 53.2% | 51.0% |
| Operating margin** | 8.8% | 8.3% | 8.4% | 8.3% | 7.0% |
| Underlying Group EBITDA*** | £103.4m | £101.1m | £109.9m | £114.6m | £108.7m |
| Net debt*** | (£110.6m) | (£99.6m) | (£61.8m) | (£47.9m) | (£85.9m) |
* The statutory 53-week period to 3 April 2015 comprises results that are non-comparable to the 52-week periods reported in other years. To provide a more meaningful comparison, the above tables include the pro forma 52 weeks to 27 March 2015.
** Operating margin is defined as results from operating activities before non-recurring items as a percentage of revenue.
*** These alternative performance measures are defined on the key performance indicators page.