Heat Map - R

I'm trying to create a value map with the following data:

ESTADOS          MATRICULAS MATRICULAS1    lon   lat
   <chr>                 <dbl>       <dbl>  <dbl> <dbl>
 1 CIUDAD DE MÉXICO     682510      0.167  - 99.1  19.4
 2 MÉXICO               454111      0.111  -103    23.6
 3 JALISCO              245681      0.0600 -103    20.7
 4 PUEBLA               242997      0.0593 - 98.2  19.0
 5 VERACRUZ             233867      0.0571 - 96.1  19.2
 6 NUEVO LEÓN           203084      0.0496 -100.0  25.6
 7 GUANAJUATO           150811      0.0368 -101    21.0
 8 SINALOA              140298      0.0343 -107    25.2
 9 CHIHUAHUA            127444      0.0311 -106    28.5
10 BAJA CALIFORNIA      119655      0.0292 -115    30.8

Where MATRICULAS are absolute data and MATRICULAS1 are relative data.

I used the following code:

mex_map <- ggmap(get_map(location = "mexico", maptype = "terrain", zoom = 5), extent = "device")

mex_map + stat_density2d(aes(x = lon, y = lat, fill = ..level.., alpha = ..level..), size = 2, bins = 4, data = df, geom = "polygon")

Generating the following chart:

There are two problems in my understanding.

First the code is creating two captions; according to the data are not being distributed throughout the country, across the various states.

Sincerely.