HAL website lists gratuity for non-suite guests as $16 (see below). This is in US dollars.
Since OP is from Canada...FYI, pre-paid crew appreciation for my upcoming trip came out to $145.60 (CAD) pp for a 7 day cruise (non-suite).
https://www.hollandamerica.com/en_US/faq.html > Under 'Shipboard Life'
Crew Appreciation is a daily (adjustable) amount added to your onboard account and pooled in order to recognize the many team members throughout our fleet who contribute to the guest experience.
The daily Crew Appreciation charge is $16.00 per guest per day for non-suite stateroom guests and $17.50 per guest per day for suite guests. The charges are subject to change without notice.
The Crew Appreciation charge is paid to Holland America Line team members and represents an important part of their compensation. An 18% service charge is automatically applied to all beverage purchases, bar retail items, specialty restaurant cover charges, all for-purchase a la carte menu items, and all Spa & Salon services. Local sales taxes are applied where required.