The following table shows the sale (in thousands) of different types of helmets by a shop over the given years.

Type of Helmet/Year	1998	1999	2000	2001	2002
A	78	45	56	63	88
B	58	64	78	60	68
C	46	54	58	76	68
D	64	68	65	72	78
E	82	66	74	80	84

What was the percentage increase in the sale of Helmets C in 2002 as compared to that in 1999?

Correct option is A

Given :
- Sale of Helmet C in 1999 = 54 thousand
- Sale of Helmet C in 2002 = 68 thousand

 Formula Used:
​$$\text{Percentage Increase} = \left( \frac{\text{Difference in Sales}}{\text{Sales in 1999}} \right) \times 100$$​​
Solution:
1. Calculate the difference in sales:
$$\text{Difference in Sales} =68 - 54 = 14 \text{ thousand}$$​​

2. Calculate the percentage increase:
$$\text{Percentage Increase} = \frac{14}{54} \times 100$$​​​​
Calculate the percentage:
​$$\text{Percentage Increase} = \frac{14}{54} \times 100 \approx 25.93\%$$​​