How to remove excess ticks in bar chart and errors help?

My bar chart is exactly the same as FCC’s in a sense that values and styling(except color and fonts) are. Hovering over particular bar shows exact same values.
Errors i’m getting are: 1, 2 and 10.

Questions:

  • Errors 1 and 2 are about tooltips. I made tooltips just like in tutorial and followed user stories, so they shouldn’t be.

  • Error 10 says: " The data-date attribute and its corresponding bar element should align with the corresponding value on the x-axis." even though bar is aligned, but since bars are so narrow i can’t tell for sure.

  • How to remove excess ticks?

Here is my pen.

Edit1:

I edited my code so only errors now are 1 and 2. Still, how to make tick values start from 1950 and to make subsequent ticks 5 years apart?

Anyroad, mucho kudos in advance.