## `summarise()` has grouped output by 'decade'. You can override using the `.groups` argument.
## `summarise()` has grouped output by 'year'. You can override using the `.groups` argument.
## `geom_smooth()` using formula 'y ~ x'
## `summarise()` has grouped output by 'year'. You can override using the `.groups` argument.
## `geom_smooth()` using formula 'y ~ x'